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REESE      IBRARY 


UNIVERSITY  OF  CALIFORNIA. 

,190     . 
Accession  No.      92350     •   Class  No. 


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INTRODUCTION 


TO 


CHEMICAL  PREPARATIONS. 

A  GUIDE  IN  THE  PRACTICAL  TEACHING 
OF  INORGANIC  CHEMISTRY. 


BY 

PROFESSOR  DR.   ERDMANN, 

OF   HALLE. 


AUTHORIZED  TRANSLATION  FROM  THE  SECOND  GERMAN  EDITION 


FREDERICK   L.  DUNLAP,  S.D., 

Instructor  in  Industrial  Chemistry  at  the  Worcester  Polytechnic  Institute. 


FIRST    EDITION. 


>xW^v  FIRST    THOUSAND. 


NEW   YORK : 

JOHN   WILEY   &   SONS. 

LONDON  :    CHAPMAN   &  HALL,  LIMITED. 

IQOO. 


Copyright,  1900, 

BY 

FREDERICK   L.   DUNLAP. 


ROBERT  DRUMMOND,    PRINTKR,   NFW  YORK. 


TRANSLATOR'S   PREFACE. 


IN  presenting1  to  the  public  this  translation  of 
Professor  Erdmann's  book,  it  is  hoped  that  in  this 
form,  which  is  more  serviceable  to  the  English-speak- 
ing student,  it  may  aid  in  advancing  the  recognition 
due  so  important  an  adjunct  in  laboratory  instruction 
in  chemistry  as  that  of  the  subject  of  inorganic 
chemical  preparations.  It  is  gratifying  to  see  that 
recognition  is  being  given  to  inorganic  chemi- 
cal preparations,  by  the  introduction  of  work  of  this 
nature  among  the  courses  of  some  of  our  educational 
institutions.  It  is  particularly  desirable  that  this  sub- 
ject be  given  a  broader  scope  than  has  hitherto  been 
afforded  it;  for  it  gives  to  the  student  a  specially 
broad  field  in  which  to  acquire  chemical  manipulation 
of  a  quite  varied  nature.  Then,  too,  with  such  a  wisely 
chosen  and  diversified  list  of  experiments  as  Professor 
Erdmann  has  made  use  of,  the  opportunity  for  the 
observation  of  phenomena  of  different  kinds  lends 
itself  admirably  to  the  development  of  chemical 
thought  in  a  perfectly  natural  way.  The  introduction 
of  the  subjects  of  qualitative  and  quantitative  analysis 

iii 

92350 


IV  TRANSLATOR'S  PREFACE. 

into  this  work,  is  accomplished  in  such  a  manner  that 
it  may,  with  the  judicious  guidance  of  the  instructor, 
help  in  preventing  these  subjects  from  degenerating 
into  a  "  blind  following  of  directions,"  as  they  not 
infrequently  do. 

The  translator  has  left  Professor  Erdmann's  book 
practically  unchanged;  a  few  foot-notes,  serviceable 
in  a  German  edition  but  less  so  in  an  English  one, 
have  been  omitted.  A  more  detailed  cross-section  of 
a  Rossler  gas-furnace  has  been  substituted  for  the 
one  used  in  the  German  edition. 

FREDERICK  L.  DUNLAP. 

WORCESTER,  MASS.,  February,  1900. 


PREFACE. 


WHEN  this  introduction  first  appeared,  it  was  but 
little  customary  to  give  the  preparation  of  inorganic 
substances  a  significant  place  in  laboratory  instruc- 
tion. It  is  true  there  never  was  a  doubt  that  the 
chemical  ideas  of  the  student  are  built  up  only  by  his 
own  observation;  but  only  in  the  special  domain  of 
the  carbon  compounds  has  the  logical  conclusion  of 
this  been  drawn.  It  was  thought  that  in  inorganic 
chemistry  one  was  able,  after  a  few  test-tube  reac- 
tions, to  go  directly  into  systematic  analysis,  which, 
in  consequence,  frequently  degenerated  into  a  blind 
following  of  directions.  In  opposition  to  this,  I  took 
the  ground  that  the  systematic  observing  and  execut- 
ing of  various  kinds  of  reactions  on  not  too  small  a 
scale,  was  the  most  valuable  means  for  the  develop- 
ment and  exercise  of  chemical  thought,  and,  conse- 
quently, must  constitute  the  basis  for  practical  in- 
struction. From  this  results  the  demand  for  selecting, 
from  a  didactic  standpoint,  preparations  from  the 
whole  field  of  chemistry.  To  the  very  carefully  pre- 


VI  PREFACE. 

pared,  reliable,  and  thorough  directions,  analytical 
hints  could  then  be  added  in  a  natural  way. 

My  first  attempt  in  this  direction  found  every- 
where such  friendly  acceptance  and  criticism  that  I 
gladly  comply  with  the  wish  of  my  publishers  for  a 
new  edition.  The  text  is  much  improved  by  kind 
communications  of  my  colleagues  and  by  my  own 
practical  experience.  The  following  preparations  are 
added  :  ammonium  perborate;  anhydrous  alumin- 
ium chloride;  thorium  dioxide;  arsenious  oxide; 
violet  chromium  sulphate;  potassium  iodate.  The 
index,  tables  of  atomic  weights,  etc.,  as  also  some  new 
illustrations,  will  contribute  to  the  usefulness  of  the 
guide. 

In  the  choice  of  the  preparations,  care  was  taken 
to  present  to  the  student  many  fundamentally  differ- 
ent reactions.  The  author  trusts  to  have  done  justice 
to  the  economy  of  the  laboratory  by  starting,  as  far 
as  possible,  with  cheap  or  valueless  materials;  for 
example,  the  residues  of  all  sorts  accumulated  in  every 
laboratory,  or  the  by-products  from  other  prepara- 
tions. The  finished  preparations  are,  on  the  other 
hand,  for  the  most  part  substances  which  are  con- 
tinually used  in  the  laboratory  in  analytical  and  syn- 
thetical processes,  but  which  are  either  not  generally 
found  in  the  market  or  else  not  obtainable  in  a  suf- 
ficiently pure  state. 

The  arrangement  of  the  guide  is  based  on  the 
natural  system  of  the  elements  (page  114).  Each  of 


PREFACE.  VI 1 

the  more  important  elements  is  represented  by  some 
characteristic  compounds,  so  that  the  student  who 
makes  a  preparation  of  each  of  the  thirty-five  elements 
considered  here,  obtains  an  idea  of  the  whole  field  of 
chemistry.  ' 

The  appendix  treats  briefly  of  a  few  of  the  most 
important  helps  in  the  laboratory,  among  other  things 
of  the  technique  of  gas  currents,  recently  so  much 
improved. 

H.  ERDMANN. 

HALLE  a.  S.,  April,  1899. 


CONTENTS. 


SODIUM. 

Sodium  amalgam,  io/£ I 

Pure  sodium  chloride,  NaCl 2 

Sodium      hydroxide      solution     free      from      carbonate, 

NaOH  +  *H20 4 

Sodium  nitrite,  NaNOa 6 

POTASSIUM. 

Chemically  pure  potassium  hydroxide,  KOH 8 

Pure  potassium  disulphate,  KHSO4 10 

Potassium  cyanate,  KCNO 10 

Potassium  chlorate,  KC1O3 13 

COPPER. 

Cuprous  chloride,  CuCl 14 

Cuprous  cyanide,  CuCN 15 

Cupric  sulphate,  CuSO4  -f-  5HaO 16 

Cuprammonium  sulphate,  CuSO4  +  4NH3  -f-  HUO 18 

Cupric  potassium  sulphate,  CuK2(SO4)2  +  6H2O 18 

SILVER. 

Pure  silver,  Ag 19 

(a)  Crystalline  silver,  according  to  Stas 19 

(b)  Molecular  silver,  from  residues 19 

GOLD. 

Pure  gold,  Au 21 

MAGNESIUM. 

Anhydrous  magnesium  chloride,  MgClj 22 

CALCIUM. 

Porous  calcium  chloride,  CaCl2 24 

Calcium  carbonate,  CaCOs 25 

ix 


X  CONTENTS. 

PAGE 

ZINC. 

Zinc  free  from  arsenic,  Zn 26 

STRONTIUM. 

Strontium  hydroxide,  Sr(OH)a -}- 8HaO 27 

CADMIUM. 

Cadmium  carbonate,  CdCOs 29 

BARIUM. 

Barium  oxide,  BaO 30 

Barium  hydroxide,  Ba(OH)a  -f8H2O 32 

Barium  peroxide,  BaO2 33 

Hydrated  barium  peroxide,  Ba(OH)4  +  6HaO 33 

MERCURY. 

Distilled  mercury,  Hg 34 

Mercuric  chloride,  HgCla  (from  residues) 37 

Mercuric  cyanide,  Hg(CN)2 38 

Mercuric  sulphide,  HgS 39 

BORON. 

Boron,  B 39 

Boric  acid,  H3BOa 40 

Ammonium  perborate,  NH4BO3  -f-  ^HaO 41 

ALUMINIUM. 

Aluminium  hydroxide,  A1(OH)3  (from  cryolite) 42 

Anhydrous  aluminium  chloride,  Aids 43 

CARBON. 

Pure  oxalic  acid,  H2C2O4  -f  2HaO 44 

Anhydrous  oxalic  acid,  H2CaO4  (sublimed) 45 

Ethyl  bromide,  CaH6Br  (free  from  arsenic) 45 

SILICON. 

Crystalline  silicon,  Si 47 

Silicon  tetrachloride,  SiCl« 48 

TIN. 

Anhydrous  stannous  chloride,  SnCla 49 

Anhydrous  stannic  chloride,  SnCU  (Spiritus  fumans  La- 

bavii) 50 

LEAD. 

Lead  peroxide,  PbOa 52 

(a)  In  a  dry  way 52 

(£)  In  a  wet  way 54 


CONTENTS.  XI 

PAGE 

THORIUM. 

Thorium  dioxide,  ThO2 55 

NITROGEN. 

Nitrogen  tetroxide,  N2O4 57 

Pure  anhydrous  nitric  acid,  HNO3 59 

Pure  ammonium  chloride,  NH4C1 60 

Ammonium  dicarbonate,  (NH^HCOs 61 

Hydrocyanic  acid,  HCN 62 

Urea,  CON2H4 63 

PHOSPHORUS. 

Phosphoric  acid,  H3PO4 64 

Phosphorus  trisulphide,  P2S3 65 

Calcium  phosphide, CaP 66 

ARSENIC. 

Arsenic  acid,  2H»AsO4  -\-  H2O 68 

Crystalline  arsenious  oxide,  As4O«. 71 

ANTIMONY. 

Antimonious  chloride,  SbCU 73 

Basic  chloride  of  antimony,  Sb^OiiCU  (powder  of  Algaroth)  74 

Sulphate  of  antimony,  Sb2(SO4)3 75 

BISMUTH. 

Bismuth  nitrate,  Bi(NO3)3  +  5H2O .' 75 

Basic  bismuth  nitrate,  BiO.NO-,  -f  BiO.OH 75 

Bismuth  hydroxide,  BiO.OH 75 

Bismuth  iodide,  BiI3 76 

Bismuth  oxyiodide,  BiOI 77 

OXYGEN. 

Hydrogen  peroxide,  H2O2 78 

SULPHUR. 

Disulphur  dichloride,  S2C1 , 80 

Sulphur  dichloride,  SC12 80 

Barium  dithionate,  BaS2O«  +  2H2O 81 

Dithionic  acid,  H2S2O«  +  ^H2O 81 

Thiophene,  C4H4S 83 

CHROMIUM. 

Anhydrous  chromic  chloride,  CrCl3 85 

Chromic  oxide,  Cr2O3 87 

Violet  chromium  sulphate,  Cr2(SO4)3-f-  i8H,0 88 

Chromyl  chloride,  CrOaCl, 89 


XI I  CONTENTS. 

PAGE 

CHROMIUM. 

Chromous  acetate,  (CH3COO)aCr 90 

Potassium  chlorchromate,  KO.CrO2.Cl gi 

SELENIUM. 

Selenium,  Se 92 

FLUORINE. 

Fluosilicic  acid,  H2SiFe 93 

CHLORINE. 

Perchloric  acid,  HC1O4 95 

BROMINE. 

Hydrobromic  acid,  HBr 96 

Ammonium  bromide,  NH4Br 98 

Potassium  bromide,  KBr 98 

Dibrombenzene,  C6H4Bra 99 

IODINE. 

Potassium  iodide,  KI » 100 

Potassium  iodate,  K2I3O6 101 

Iodine  trichloride,  IC13 102 

Iodine  pentoxide,  IaO6 103 

MANGANESE. 

Metallic  manganese,  Mn 104 

Manganous  chloride,  MnCla  +  4H2O 107 

IRON. 

Anhydrous  ferrous  chloride,  FeCl2 108 

Anhydrous  ferric  chloride,  FeCls 109 

Anhydrous  ferrous  bromide,  FeBra no 

Iron  ammonium  alum,  Fe(NH4)(SO4)2  -{-  I2H2O in 

in     ii 

Prussian  blue,  Fe4[Fe(CN)6]3 112 

PLATINUM. 

Chlorplatinic  acid,  H2PtCl«  (from  residues) 113 

APPENDIX 115 

Sources  of  heat 115 

Cooling  mixtures 118 

Gas  currents 119 

Gas  currents  from  Kipp  apparatus 121 

Gas  currents  from  the  apparatus,  Figure  10 122 

Purification  of  gas  currents 124 

Use  of  liquefied  gases 125 

Introduction  of  gases  into  liquids 126 


CONTENTS.  Xlll 

PACK 

ATOMIC  WEIGHTS  OF  THE  74  ELEMENTS 128 

INDEX  OF  AUTHORS 131 

INDEX 133 


ILLUSTRATIONS. 

FIGURE 

1.  Distillation  of  mercury  in  vacuo 35 

2.  Air-tight  mercury  trap 36 

3.  Preparation  of  anhydrous  stannic  chloride 51 

4.  Preparation  of  pure  anhydrous  nitric  acid 58 

5.  Preparation  of  calcium  phosphide 67 

6.  Preparation  of  anhydrous  chromic  chloride 85 

7.  Preparation  of  hydrobromic  acid 96 

8.  Gas-stove  for  gentle  heating 115 

9.  Cross-section  of  the  Rossler  gas-furnace 117 

10.  Preparation  of  gases  by  the  interaction  of  two  liquid  sub- 

stances     I2O 

11.  Mercury  trap 120 

12.  Apparatus  for  the  evolution  of  chlorine 123 

13.  Gas  washing-bottle 124 

14.  Tube  for  the  introduction  of  gases  into  liquids 126 

15.  Absorption  of  troublesome  gases . .   127 


TABLES. 

SPECIFIC  GRAVITY  OF  SODIUM  HYDROXIDE 5 

SOLUBILITY  OF  POTASSIUM  CYANATE 13 

PERIODIC  SYSTEM  OF  THE  ELEMENTS 1 14 

MATERIAL    AND    APPARATUS    FOR  THE   EVOLUTION   OF   GAS 

CURRENTS 121,  122 

ATOMIC  WEIGHTS 128 


INORGANIC  CHEMICAL  PREPARATIONS, 


SODIUM  AMALGAM,   10%. 

Heat  3  kilograms  of  mercury  strongly. with  a  Berlin 
burner  (see  appendix),  in  a  covered  iron  pot  under 
a  hood,  and  add,  in  rapid  succession,  300  grams  of 
sodium  *  cut  into  pieces  of  about  5  grams  each.  At 
each  addition  of  sodium,  the  reaction  must  take  place 
immediately,  accompanied  by  a  flash.  If  towards  the 
end  of  the  operation  this  ceases  to  be  the  case,  in- 
crease the  heat  and  stir  with  an  iron  rod.  After  all  the 
sodium  has  been  added,  pour  the  amalgam  upon  an 
iron  plate,  break  it  into  pieces,  and  put  it  into  a  thick- 
walled,  well-stoppered  flask  while  it  is  still  warm. 

REACTION:  The  union  of  the  metals  takes  place 
very  easily,  so  long  as  the  mass  is  completely  liquid; 

*  Sodium  is  best  protected  under  low  boiling  petroleum  ether 
(ligroin)  and  not  under  petroleum.  Sodium  waste  can  be  used 
quite  well  at  the  beginning  of  the  experiment  if  it  is  washed 
with  ligroin  and  superficially  dried  with  coarse  blotting-paper. 
Upon  pouring  out  the  amalgam,  the  impurities  in  the  sodium 
remain  as  a  carbonaceous  residue  in-  the  iron  pot. 


2  INORGANIC  CHEMICAL   PREPARATIONS. 

but  when  crusts  of  unmelted  amalgam  form,  in  con- 
sequence of  too  little  heat,  the  unchanged  pieces  of 
sodium  may  collect  upon  it.  This  must  be  avoided 
by  stirring. 

TEST:  Place  pieces  of  the  amalgam  broken  up  to 
the  size  of  a  pea  in  a  small  weighing-bottle,  and  weigh. 
0.3-0.5  gram  from  it  into  a  dry  nitrometer  tube. 
Place  dilute  sulphuric  acid  in  the  cup  of  the  nitrom- 
eter and  measure  the  hydrogen  evolved  upon  shak- 
ing. 


PURE   SODIUM    CHLORIDE,    NaCl. 

Triturate  \  kilogram  of  common  salt  with  i^  liters 
of  cold  water  in  a  mortar  of  3  liters  content,  filter 
through  a  creased  filter  into  a  3-liter  porcelain  dish, 
and  heat  on  the  gas-stove.  Add  5  grams  of  lime  in 
the  form  of  milk  of  lime,  and  then  treat  with  barium 
chloride  until  there  is  a  slight  excess.*  After  the  pre- 
cipitate settles,  filter  into  a  beaker  and  add  sodium 
carbonate  solution  (made  from  15  grams  of  pure  an- 

*  On  an  average,  12  grams  of  crystallized  barium  chloride  are 
used.  As  it  is  very  difficult  to  recognize  the  end  of  the  reaction 
in  the  turbid  liquid,  a  small  test  is  withdrawn,  as  is  done  in  many 
other  cases,  by  dipping  a  fine  capillary  tube  in  at  the  edge  of 
the  liquid  where  it  rapidly  settles.  By  blowing,  the  contents  of 
the  capillary  tube  are  emptied  upon  a  watch-glass.  In  the  case 
in  question-,  the  watch-glass  is  placed  on  a  black  background 
and  tested  with  a  drop  of  barium  chloride  solution  and  with 
dilute  sulphuric  acid. 


INORGANIC  CHEMICAL   PREPARATIONS.  3 

hydrous  sodium  carbonate).  Bring  this  filtrate  to  the 
boiling  point,  neutralize  with  dilute  hydrochloric 
acid  (about  25  c.c.),  and  evaporate  as  rapidly  as  possi- 
ble, by  means  of  a  large  flame,  to  -J  liter.  Collect, 
in  a  funnel  containing  a  platinum  cone,  the  sodium 
chloride  which  separates;  drain  it  by  means  of  a  filter- 
pump;  and  dry  the  salt  by  heating  in  a  platinum  or 
porcelain  dish,  stirring  with  a  platinum  spatula  or 
glass  rod. 

REACTION:  The  magnesium,  as  well  as  any  iron 
present  in  the  common  salt,  is  precipitated  by  the 
milk  of  lime  as  a  hydroxide: 

MgQ2  +  Ca(OH)2  =  Mg(OH)2  +  CaQ2; 

the  sulphuric  acid  is  precipitated  by  means  of  the 
barium  chloride: 

CaSO4  +  BaCl2  =  BaSO4  +  CaQ2; 

the  alkaline  earths  are  finally  separated  as  carbonates: 

CaCl2  +  Na2CO3  =  CaCO3  +  2NaCl. 

TEST:  Sodium  chloride  consists  of  a  snow-white 
crystalline  powder  made  up  of  fine  cubes.  The  dried 
salt  should  not  decrepitate  or  give  off  water  upon 
being  heated  in  a  small  dry  tube.  At  a  higher  tem- 
perature it  should  melt  to  a  mobile  fluid.  Test  the 
aqueous  solution  with  ammonium  oxalate,  sodium 
phosphate,  potassium  ferrocyanide,  and  barium  dhlo- 
ride,  for  the  absence  of  calcium,  magnesium,  iron,  and 


4  INORGANIC  CHEMICAL   PREPARATIONS. 

sulphuric  acid.  One  drop  of  the  solution  and  ten 
drops  of  platinic  chloride,  evaporated  on  a  watch- 
glass  to  a  small  volume,  should  give,  upon  cool- 
ing, pretty  triclinic  prisms  of  sodium  chlorplatinate, 
Na2PtCl6  +  6H2O,  which  upon  dissolving  in  alcohol 
should  leave  no  residue  of  potassium  ehlorplatinate. 


SODIUM    HYDROXIDE    SOLUTION    FREE 
FROM  -CARBONATE,   NaOH  + 


Place  250  grams  of  lime  (best  made  from  marble) 
in  a  small  iron  pot,  pour  a  little  hot  water  upon  the 
lime,  and  cover  the  vessel.  Then  dissolve,  by  heating, 
i  kilogram  of  commercial  sodium  hydroxide  in  3  liters 
of  water,  in  an  iron  pot  of  5-6  liters  content.  Make 
milk  of  lime  from  the  lime,  which  has  meanwhile 
fallen  to  a  powder,  by  stirring  i  liter  of  hot  water  with 
it;  then  add  this  milk  -of  lime  to  the  boiling  sodium 
hydroxide  solution.  Pour  this  solution  into  a  tall  flask 
or  cylinder,  which  has  been  previously  warmed  by 
rinsing  out  with  hot  water,  and  close  the  receptacle 
tightly  with  either  a  stopper  or  -a  ground-glass  plate. 
The  next  day,  siphon  the  liquid,  which  is  completely 
clear,  into  a  3-liter  flask,  the1  siphon  being  at  first 
filled  with  water. 

REACTION:  Carbonic  acid  and  silicic  acid  are  pre- 
cipitated as  insoluble  salts  by  the*  lime. 

TEST:    The  sodium  hydroxide  solution  should  re- 


INORGANIC  CHEMICAL   PREPARATIONS. 


5 


main  clear  upon  the  addition  of  a  drop  of  barium  chlo- 
ride solution  (carbonic  acid,  sulphuric  acid).  Con- 
cerning the  remaining  impurities  in  sodium  hydrox- 
ide (ammonia,  lime-,  iron,  copper,  aluminium  hydrox- 
ide, silica),  compare  with  potassium  hydroxide,  page 
9.  The  strength  of  the  sodium  hydroxide  solution 
may  be  ascertained  approximately,  by  means  of  the 
specific  gravity,  from  the  following  table.* 


Per  Cent 
NaOH. 

Specific 
Gravity. 

Per  Cent 
NaOH. 

Specific 
Gravity. 

Per  Cent 
NaOH. 

Specific 
Gravity. 

10 

•  US 

17 

.192 

24 

1.296 

II 

.126 

18 

.202 

25 

.279 

12 

•  137 

19 

.213 

26 

.290 

13 

.148 

20 

.225 

27 

.300 

14 

•  159 

21 

.236 

28 

•  310 

15 

.170 

22 

.247 

29 

.321 

16 

.181 

23 

.258 

30 

•332 

To  determine  the  amount  of  sodium- hydroxide  pres- 
ent, fill  a  burette  with  this  solution  and  another  with 
dilute  hydrochloric  acid,  and  determine  the  equiva- 
lent of  both-  liquids  (using  phenolphthale'in  as  an  indi- 
cator) by  titrating  20  c.c.  of  the  sodium  hydroxide 
solution-  with  the  acid,  until  it  is  colorless.  Weigh 
10.585  grams  (Vio  niol.)  of  ignited  pure  sodium  car- 
bonate, add  an  excess  -of  the  dilute  hydrochloric  acid 
from  the  burette,  heat,  and  then  titrate  back  with  the 
sodium  hydroxide  solution.  A  simple  calculation 

*  For  the  specific  gravity  of  weaker  and  stronger  sodium  hy- 
droxide solutions,  see  Erdmann.  Lehrbuch  der  anorganischen 
Chemie  (Braunschweig  1898),  page  528. 


0  INORGANIC  CHEMICAL   PREPARATIONS. 

gives  the  strength  of  the  acid  and  the  sodium  hydrox- 
ide. If  the  strength  of  a  sodium  hydroxide  solution 
containing  some  carbonate  is  to  be  determined,  add  5 
c.c.  of  barium  chloride  solution  to  20  c.c.  of  the  sodi- 
um hydroxide  solution  before  titrating  with  phe- 
nolphthalein  as  an  indicator. 


SODIUM    NITRITE,    NaNO2. 

After  removing  the  small  dome  from  the  inner  fire- 
clay mantle  of  a  Rossler  gas-furnace,  place  upon  the 
mantle  a  strong  iron-wire  triangle,  and  set  upon  the 
triangle  a  shallow  iron  dish  (2^  cm.  high,  12  cm. 
upper  diameter)  having  a  smooth  bo'ttom.  Place  85 
grams  of  Chili  saltpetre  in  the  dish  and  close  the 
furnace.  As  soon  as  the  dish  has  become  faintly  in- 
candescent and  the  molten  nitrate  just  begins  to  give 
off  bubbles  of  oxygen,  gradually  add  206  grams  of  lead 
in  the  form  of  old  pieces  of  sheet  lead  or  lead  tubing. 
The  lead  is  at  once  vigorously  oxidized,  and,  if  stirred 
continually  with  an  iron  spatula,  becomes  almost  com- 
pletely converted  into  oxkle  of  lead  in  half  an  hour. 
Empty  the  contents  of  the  small  iron  dish  into  a  large 
deep  iron  one,  and  repeat  the  operation  several  times, 
using  the  same  amounts  of  Chili  saltpetre  and  lead. 
Place  the  various  products  in  the  large  iron  dish,  ex- 
tract once  with  boiling  water,  and  decant  upon  a 
creased  filter.  Dry  the  residue  of  lead  oxide  and  set 


INORGANIC  CHEMICAL   PREPARATIONS.  7 

aside  for  the  experiment  on  page  52.  Pass  a  strong 
current  of  carbon  'dioxide  into  the  still  boiling-hot 
filtrate,  for  a  few  minutes  only;  filter  off  the  lead 
carbonate  which  separates,  and  neutralize  the  solu- 
tion while  stirring  it,  by  carefully  adding  nitric  acid 
from  a  pipette  or  burette.  Evaporate  the  solution  to 
crystallization.  The  crystals  which  separate  first,  con- 
sist partly  of  nitrate  and  may  be  used  again  for  re- 
melting  with  lead;  the  mother-liquor  gives  pure 
nitrite.  A  normal  solution  -of  the  nitrite  is  prepared 
by  dissolving  69  grams  of  it  in  water  and  diluting  to 
one  liter. 

REACTION  :  NaNO3  +  Pb  =  NaNO2  +  PbO.  A 
small  part  of  the  nitrite  is  converted  into  sodium 
plumbite,  which  must  be  decomposed  by  carbon  di- 
oxide. —  Nitrous  acid  reacts  with  peroxides  and  with 
permanganate  according  to  the  following  equations: 

MnO2  +  HNO2  +  HNO3  =  Mn(NO3)2  +  H2O; 
2  =  2Mn(NO3)2+HNO3+3H2O; 


with  sulphanilic  acid  it  gives  diazobenzenesulphonic 
acid  : 

/NH2  N  =  N 

C6H4<  +  HN02  -  C6H4<  >  +  2H20. 

XSO3H  X   SO3  / 

TEST:  Sodium  nitrite  crystals,  upon  treatment  with 
dilute  mineral  acids,  go  very  easily  into  solution,  with 
considerable  effervescence  and  evolution  of  nitrous 
anhydride.  The  acid  solution  turns  potassium  iodide 


8  INORGANIC  CHEMICAL  PREPARATIONS. 

and  starch  paper  blue  and  dissolves  the  peroxides  of 
manganese  and  lead  with  great  rapidity.  To  test 
the  strength  of  the  sodium  nitrite,  fill  a  burette  with 
the  normal  solution  and  run  it  into  a  solution  of 
11.55  grams  of  the  sodium  salt  of  sulphanilic  acid, 
C6H4NH2.SO3Na  +  2H2O,  which  is  cooled  with  ice 
and  made  strongly  acid  with  hydrochloric  acid;  stir 
constantly,  and  continue  the  addition  of  the  nitrite  so- 
lution until  a  drop  of  the  liquid  gives  a  strong  blue 
color  with  potassium  iodide  and  starch  paper.  If  the 
nitrite  is  pure,  50  c.c.  are  necessary.  Or,  50  c.c.  of  the 
nitrite  solution  may  be  measured  into  a  graduated 
flask  by  means  of  a  pipette,  diluted  to  one  liter,  and 
this  dilute  solution  run  from  a  burette  into  tenth  nor- 
mal permanganate  which  is  made  acid  with  sulphuric 
acid  and  warmed  to  40-50°,  stirring  during  the  addi- 
tion. Just  50  c.c.  of  the  twentieth  normal  nitrite 
solution  should  be  used  for  50  c.c.  of  the  permanga- 
nate. 


CHEMICALLY    PURE   POTASSIUM 
HYDROXIDE,   KOH. 

Literature:    Schubert,  Jour.  f.  pract.  Chem.  [2]  26,  117. 

Dissolve  300  grams  of  crystallized  barium  hydrox- 
ide in  i  liter  of  water  in  an  iron  dish,  and  add  a  hot 
concentrated  solution  of  120  grams  of  potassium  sul- 


INORGANIC  CHEMICAL  PREPARATIONS.  9 

phate  until  a  test  taken  out  by  means  of  a  capillary 
tube  (see  no'e  on  page  2)  reacts  with  neither  a  po- 
tassium sulphate  nor  a  barium  hydroxide  solution. 
Filter  through  a  creased  filter  into  a  glass  flask;  and 
evaporate  the  filtrate  in  separate  portions  in  a  silver 
crucible  as  rapidly  as  possible,  by  means  of  a  large 
flame.  When  the  potassium  hydroxide  which  remains 
is  in  a  state  of  quiet  fusion,*  pour  it  into  a  large  dish 
of  silver,  iron,  or  nickel,  rotate  it,  and  put  the  thin 
plates,  while  still  hot,  into  a  preparation  bottle  which 
is  to  be  well-stoppered  and  paraffined. 

REACTION:  Ba(OH)2  +  K2SO4  =  2KOH  +  BaSO4. 

TEST:  The  potassium  hydroxide  should  dissolve  in 
water  and  alcohol  without  turbidity;  a  solution  in 
recently  boiled  distilled  water  should  produce  no  pre- 
cipitate upon  adding  a  drop  of  barium  chloride,  sul- 
phuric acid,  ammonium  sulphide,  or  Nessler's  re- 
agent. Upon  heating  with  an  excess  of  ammonium 
chloride  solution  in  a  platinum  or  porcelain  dish  until 
almost  all  the  ammonia  has  been  driven  off,  no  pre- 
cipitate should  be  formed  (aluminium  hydroxide, 
silica);  and  one  should  not  be  produced  upon  addi- 
tion of  ammonium  oxalate  (lime). 


*  In  all  work  with  molten  alkaline  hydroxides,  it  is  necessary 
to  protect  the  eyes  by  means  of  goggles. 


1O          INORGANIC  CHEMICAL   PREPARATIONS. 

PURE   POTASSIUM   DISULPHATE,   KHSO4. 

Literature:    Kriiss,  Annalen,  238,  50. 

Commercial  potassium  chloride  is  purified  accord- 
ing to  the  method  given  for  sodium  chloride  (page 
2).  Upon  cooling  the  evaporated  solution,  most  of 
the  salt  crystallizes  out.  Determine  by  the  flame  test 
whether  or  not  this  salt  is  completely  free  from 
sodium  chloride.  Add  20  grams  of  the  pure  potas- 
sium chloride  thus  obtained,  by  means  of  a  platinum 
spoon,  to  a  platinum  dish  containing  28  grams  of 
pure,  warm,  concentrated  sulphuric  acid,  and  heat 
the  dish  with  a  small  Bunsen  flame  until  the  gas  evo- 
lution -has  completely  ceased.  The  molten  mass 
solidifies  to  a  mass  of  large  crystals. 

REACTION:  KC1  +  H2SO4  =  HC1  +  KHSO4. 

TEST:  The  snow-white  crystalline  mass  is  to  be 
tested  for  the  absence  of  sodium  and  chlorine.  De- 
termine its  melting-point,  which  lies  somewhere  above 


100°.* 


POTASSIUM   CYANATE,   KCNO. 

Literature:    Erdmann,  Berichte  d.  d.  chem.  Ges.  26,  2438,  and 
Chemische  Praparatenkunde  (Stuttgart  1894),  Bd.  II,  537. 

Break    commercial    potassium    ferrocyanide    into 
rather  coarse  pieces  and  spread  it  in  a  thin  layer  in 

*  This  varies  greatly,  even  if  the  salt  contains  only  a  small 
amount  of  water. 


INORGANIC  CHEMICAL   PREPARATIONS.  II 

a  large  iron  or  nickel  dish  or  pan;  heat  on  the  gas- 
stove  with  a  small  flame  until  the  crystals  have  com- 
pletely effloresced  and,  upon  breaking  open  the  crys- 
tals, no  core  of  the  unchanged  yellow  salt  is  present. 
Grind  the  salt  while  still  warm  to  a  fine  powder;  again 
spread  it  on  the  hot  metal  surface,  and  dry  it  at  a  uni- 
form temperature  for  a  few  hours.  Thoroughly  mix 
200  grams  of  the  absolutely  anhydrous  potassium  fer- 
rocyanide  thus  obtained,*  with  150  grams  of  potas- 
sium dichromate  which  has  previously  been  melted 
and  which  is  still  warm.  Add  the  mixture,  in  small 
spoonfuls,  to  a  large  iron  dish,  heated  by  means  of  a 
Berlin  burner  or  gas-stove  (see  appendix)  to  such  an 
extent  that  each  portion  of  the  powder,  as  it  is  added, 
changes  to  a  black  mass.  During  the  addition,  stir 
with  an  iron  spatula.  The  temperature  should  not 
rise  high  enough  to  melt  the  mass,  nor  should  am- 
monia be  evolved  during  the  operation  (shows  pres- 
ence of  water  in  the  substances).  Grind  the  black 
product  from  the  reaction  while  it  is  still  warm,  and 
then  heat  on  a  water-bath  for  10  minutes  with  a  mix- 
ture of  900  c.c.  of  80%  alcohol  and  100  c.c.  of  methyl 
alcohol,  shaking  thoroughly  during  the  operation. 
Decant  the  clear  solution  through  a  creased  filter  into 
a  large  beaker  which  is  surrounded  by  ice,  also  im- 

*  It  is  necessary  that  the  preparation  contain  no  trace  of 
water,  as  may  be  determined  by  heating  some  in  a  test-tube, 
for  the  colorless  salt  which  is  completely  effloresced  retains 
tenaciously  a  small  amount  of  water. 


12          INORGANIC  CHEMICAL   PREPARATIONS. 

mediately  cooling  the  black  residue  from  the  extrac- 
tion by  placing-  the  flask  in  ice-water.  Decant  the 
mother-liquor  from  the  heavy  crystalline  cyanate 
back  upon  the  black  residue,  and  exhaust  this  residue 
of  cyanate  by  four  or  five  similar  extractions.  Drain 
the  various  portions  of  cyanate  on  the  same  filter  by 
means  of  a  pump,  wash  with  ether,  and  dry  in  vacuo 
over  sulphuric  acid.  In  this  way  are  obtained  about  85 
grams  of  pure,  dry  potassium  cyanate  which  reacts 
only  sligMy  alkaline.  The  mother-liquor  still  con- 
tains potassium  cyanate,  which  can  only  be  obtained 
by  evaporation  in  vacuo.  It  is  better  immediately  to 
work  the  cyanate  up  into  urea  (page  63),  as  it  decom- 
poses rapidly  upon  standing  and  especially  upon  heat- 
ing, a  decomposition  which  makes  itself  evident  by 
the  odor  of  ammonia. 

REACTION:    K4Fe(CN)6  +  2K2Cr2O7 

=  6KCNO  +  2Cr2O3  +  FeO  +  K2O. 

Owing  ta  its  insolubility,  the  potassium  ferrocya- 
nide  remains  behind  in  the  process  of  crystallizing 
from  alcohol.  The 'hot  solution  must  be  rapidly  cooled; 
for,  by  long  heating,  the  water  in  the  dilute  alcohol 
decomposes  the  cyanate: 

KCNO  +  2H2O  =  K(NH4)CO3. 

Besides  the  complete  dryness  of  the  raw  material 
and  the  choice  of  a  proper  solvent,  great  rapidity  in 
the  operation  of  extraction  is  the  most  essential  con- 
dition for  obtaining  a  good  yield  of  potassium  cya- 


INORGANIC   CHEMICAL   PREPARATIONS.  13 

nate.  It  is  not  to  be  recommended,  therefore,  to  un- 
dertake this  operation  on  a  larger  scale  than  is  here 
specified. 

TEST:  The  salt  is  analyzed  by  evaporating  a  sample 
with  concentrated  sulphuric  acid  and  igniting  the 
residual  potassium  sulphate,  with  the  addition  of  a 
small  piece  of  ammonium  carbonate. 


Behavior  of  Potassium  Cyanate  towards 

Solvents. 

At  the  boiling- 
point  there 
dissolves 

Upon  cooling- 
there  crystal- 
lizes 

80$  alcohol    pure      .    

62  grams 

32  grams 

"          "           with  10$  methyl  alcohol.  . 
"       "    acetone  

76        " 

82 

37 
13 

Dissolve  a  few  small  crystals  of  potassium  cyanate 
in  alcohol  and  treat  with  a  drop  of  cobalt  acetate  solu- 
tion: the  formation  of  the  double  salt,  CoK2(CNO)4, 
is  recognized  by  the  intense  blue  color. — Concerning 
the  action  of  ammonium  sulphate,  see  page  63. 


POTASSIUM    CHLORATE,    KC1O3. 

Dissolve  100  grams  of  potassium  carbonate  in  the 
smallest  possible  quantity  of  hot  water  in  a  small  flask, 
and  pass  chlorine  into  the  boiling  liquid  until  the 
alkaline  reaction  of  the  solution  disappears.  Dilute 
with  hot  water  to  a  volume  of  350  c.c.,  filter,  and  allow 
it  to  crvstallize. 


14       INORGANIC  CHEMICAL  PREPARATIONS. 

REACTION: 

3K2C03  +  6C1  =  KC103  +  sKCl  +  3CO2. 

The  potassium  chloride  remains  in  the  mother- 
liquor.  Upon  heating,  potassium  chlorate  goes 
over  into  potassium  chloride  with  the  intermediate 
formation  of  potassium  perchlorate,  the  potassium 
chloride  volatilizing  at  a  strong  red  heat. 

TEST:  Heat  a  weighed  sample  of  the  dried  salt  in  a 
covered  platinum  crucible,  first  on  the  gas-stove  and 
then  with  the  small  flame  of  a  Bunsen  burner,  until 
it  just  reaches  red  heat.  Avoid  taking  off  the  cover 
of  the  hot  crucible. 


CUPROUS   CHLORIDE,   Cu'Cl. 

Treat  42  grams  of  cupric  chloride  (crystallized) 
and  32  grams  of  metallic  copper  (granulated  or  turn- 
ings) with  100  c.c.  of  hot  water,  add  200  c.c.  of  com- 
mercial hydrochloric  acid  (Sp.  Gr.  1.175),  and  gently 
boil  on  the  gas-stove  until  colorless,  the  flask  being 
nearly  closed  with  a  small  funnel,  through  which, 
toward  the  close  of  the  operation,  add  fuming  hydro- 
chloric acid.  This  operation  lasts  from  one  to  two 
hours,  but  is  substantially  hastened  if,  for  the  com- 
pletion of  the  reaction,  there  is  added,  in  the  form  of 
a  paste,  the  copper  powder  which  is  obtained  as  a 
by-product  "in  the  preparation  of  copper  sulphate 
(page  1 6).  Pour  the  colorless  liquid  from  the  excess 


INORGANIC   CHEMICAL   PREPARATIONS.  15 

of  copper  into  a  tall  cylinder  filled  with  cold  distilled 
water;  immediately  decant  the  curdy  cuprous  chloride 
which  precipitates  after  it  settles,  drain  rapidly  by 
means  of  a  pump,  wash  with  alcohol  and  ether,  and 
dry  in  vacuo  over  sulphuric  acid. 

REACTION:  CuCl2  +  Cu  =  2CuCl. 

TEST:  Cuprous  chloride  is  a  white,  heavy  sub- 
stance, insoluble  in  water,  easily  oxidizing  in  the  air, 
and  readily  going  into  solution  by  use  of  chlorine 
water  or  aqua  regia,  forming  cupric  chloride.  Upon 
heating  in  a  small  tube,  cuprous  chloride  melts  with- 
out decomposition. 


CUPROUS  CYANIDE,  CuCN. 

Dissolve  50  grams  of  crystallized  cupric  sulphate 
in  300  c.c.  of  hot  water;  drop  into  the  hot  solution 
in  a  flask,  by  means  of  a  drop-funnel,  a  solution  of 
26  grams  of  potassium  cyanide  in  50  c.c.  of  water.  In 
order  not  to  be  troubled  by  the  poisonous  gas  which 
is  evolved  with  considerable  foaming,  conduct  the 
cyanogen  through  an  ascending  tube  which  is  drawn 
out  to  a  fine  point;  and  as  soon  as  the  apparatus  is 
filled  with  the  gas,  burn  it  at  the  small  opening. 
Separate  the  white  curdy  precipitate  by  decanting  off 
the  solution,  which  is  still  blue  in  color,  wash  it  with 
water,  and  dry  on  a  porous  plate. 


1 6  INORGANIC  CHEMICAL   PREPARATIONS. 

REACTION:  CuSO4  +  2KCN  =  Cu(CN)2+K2SO4; 
2Cu(CN)2  =  2CuCN  +  (CN)2. 

TEST:  Cuprous  cyanide  is  quite  stable  in  the  air; 
otherwise  the  white  powder  resembles  cuprous  chlo- 
ride. It  decomposes  upon  heating,  giving  off  the  odor 
of  cyanogen. 


CUPRIC    SULPHATE,    CuSO4  +  sH2O. 

Heat  200  grams  of  copper  (granulated)  in  a  flask 
on  the  gas-stove  with  900  grams  of  concentrated  sul- 
phuric acid.*  Wash  the  sulphur  dioxide  which  is 
evolved  with  water,  and  dissolve  in  4  liters  of  cold 
water  (aqueous  sulphurous  acid).  After  cooling,  pour 
the  cupric  sulphate,  which  remains  behind  as  a  crys- 
talline white  powder,  and  the  sulphuric  acid  into  a 
porcelain  dis'h;  rinse  the  flask  with  i  liter  of  hot  water, 
whereupon  a  small  residue  of  copper  which  has  not 
been  acted  'upon  is  left  in  the  flask.  Treat  the  hot 
liquid  with  commercial  nitric  acid  (about  25  grams) 
until  a  clear  blue  solution  is  formed;  then  filter 
through  a  creased  filter  into  a  dish.  Dissolve  the 
large  crystals  which  settle  out  upon  standing  and 
which  are  somewhat  white,  in  300  c.c.  of  hot  water; 


*  In  case  it  is  not  a  question  of  the  yield  of  sulphurous  acid, 
take,  in  place  of  the  200  grams  of  copper,  300  grams  of  copper 
scale,  by  means  of  which  the  yield  of  cupric  sulphate  is  in- 
creased. 


INORGANIC  CHEMICAL   PREPARATIONS.  17 

and  by  shaking  in  a  flask  and  cooling  with  water,  a 
fine  crystalline  precipitate  is  obtained.  Filter  this 
on  a  platinum  cone  and  dry  on  a  porous  plate  with- 
out warming  (105  grams).  If  it  is  desired  to  ob- 
tain the  pure  product  in  a  prettier  form,  crystallize 
again  from  water.  Unite  the  mother-liquors  in  a 
porcelain  dish,  and  treat  in  the  cold,  stirring  well, 
with  zinc  dust,  until  the  liquid  is  only  a  faint  blue 
color.  Purify  the  copper  powder  thus  obtained  by 
decantation,  and  preserve  in  the  form  of  a  paste.  (See 
cuprous  chloride,  page  14.) 

REACTION: 

Cu  +  2H2S04  =  CuSO4  +  S02  +  2H2O. 

A  portion  of  the  sulphur  dioxide  is  further  reduced, 
forming  cttpric  sulphide,  which  is  again  decomposed 
by  the  nitric  acid  that  is  added.  From  a  concentrated 
sulphuric  acid  solution,  cupric  sulphate  separates  an- 
hydrous and  completely  white;  from  dilute  acid,  it 
separates  in  light  blue  crystals  which  contain  only  a 
small  amount  of  water. 

TEST:  Cupric  sulphate  forms  azure,  oblique  rhom- 
bohedral  crystals,  which  slowly  effloresce  in  the  air. 
By  heating  the  powdered  vitriol  upon  the  gas-stove, 
the  completely  anhydrous  sulphate  is  obtained,  which 
upon  ignition  goes  over  into  the  black  oxide.  Iron  is 
tested  for  by  means  of  an  excess  of  ammonia,  and 
zinc  by  precipitation  with  an  excess  of  sodium  hy- 
droxide and  treatment  of  the  filtrate  with  ammonium 
sulphide. 


/0*l^  X 

f  UNIVERSITY! 

V  ^,   \**&/ 


1 8          INORGANIC   CHEMICAL   PREPARATIONS. 


CUPRAMMONIUM   SULPHATE, 

CuS04  +  4NH3  +  H20. 
CUPRIC  POTASSIUM   SULPHATE, 

CuK2(SO4)2  +  6H2O. 

Ammonium  Double  Salt. — Dissolve  30  grams  of 
cupric  sulphate  in  100  c.c.  of  ammonium  hydroxide  of 
0.962  specific  gravity. — Place  150  c.c.  of  alcohol  in 
a  tall  narrow  cylinder;  then  carefully  run  in  20  c.c. 
of  water  underneath  the  alcohol,  by  means  of  a  drop- 
funnel  having  a  long  stem;  and  finally  add  the  cupric 
sulphate  solution  in  a  small  stream,  so  that  it  collects 
at  the  bottom  of  the  cylinder,  being  separated  from 
the  alcohol  by  the  layer  of  water.  While  standing 
quietly  from  one  to  four  weeks,  large  deep  blue  crys- 
tals form. 

Potassium  Double  Salt. — Mix  a  saturated  solution  of 
100  grams  of  cupric  sulphate,  made  at  a  temperature 
of  70°,  with  a  similar  solution  of  69.8  grams  of  potas- 
sium sulphate,  the  latter  solution  being  prepared  with 
the  addition  of  7  c.c.  of  concentrated  sulphuric  acid. 
Upon  cooling,  the  light  blue  crystals  of  the  double 
salt  separate. 

TEST:  For  testing,  determine  the  amount  of  copper 
in  the  salts:  in  the  case  of  the  ammonium  double 
salt,  by  simple  ignition  and  weighing  the  .resulting 
copper  oxide;  with  the  potassium  double  salt,  by 
precipitation  from  a  dilute  solution,  made  slightly 


INORGANIC   CHEMICAL   PREPARATIONS.  1 9 

acid  with  hydrochloric  acid,  in  a  small  weighed  plat- 
inum dish,  by  means  of  a  little  piece  of  cadmium  or 
zinc.  When  a  small  test  of  the  decolorized  liquid  no 
longer  gives  a  precipitate  of  cupric  sulphide  with 
hydrogen  sulphide,  wash  with  hydrochloric  acid,  then 
with  hot  water,  and  finally  with  alcohol;  dry  at  100° 
and  weigh. 


PURE  SILVER,  Ag. 

(a)  Crystalline  Silver  according  to  Stas. — Dissolve 
in  nitric  acid  any  desired  but  known  weight  of  silver 
which  contains  copper  (coin  or  scrap),  such  as  is  used 
in  the  arts;  filter,  and  evaporate  to  dryness.    Heat  the 
residue  until  it  melts  and  begins  to  turn  black;   take 
up  in  water,  filter,  and  dilute  until  the  liquid  contains 
2%  of  silver.     Make  the  cold  solution  strongly  am- 
moniacal  and  add  sufficient  40%  sodium  disulphite, 
so  that  a  test  of  the  blue  liquid  decolorizes  upon  heat- 
ing. 

Upon  letting  the  solution  stand  in  the  cold,  the 
greater  part  of  the  silver  precipitates  in  beautiful  crys- 
tals, the  rest  of  it  precipitating  upon  warming  from 
60°  to  70°.  Wash  the  silver  with  cold  water,  digest 
once  with  concentrated  ammonia,  wash  again  with 
water,  dry  on  the  water-bath,  and  weigh. 

(b)  Molecular   Silver   from  Residues. — Heat   silver 
residues  with  zinc  bars  and  hydrochloric  acid:   sepa- 


20          INORGANIC  CHEMICAL   PREPARATIONS, 

rate  mechanically  the  reduced  silver  from  the  undis- 
solved  zinc,  wash  well  by  decantation,  dissolve  in 
nitric  acid,  and  precipitate  with  hydrochloric  acid. 
Wash  the  silver  chloride  which  separates  'by  decanta- 
tion and  add,  while  still  moist,  to  'a  sodium  hydrate 
solution  which  is  kept  boiling-  in  a  porcelain  dish, 
adding-  to  this  hot  solution  from  time  to  -time  a  few 
cubic  centimeters  of  a  concentrated  grape-sugar  solu- 
tion, until  a  sample  of  the  gray  silver  powder,  which 
has  been  filtered  and  washed,  dissolves  clear  in  nitric 
acid.  Wash,  dry,  and  weigh  as  under  (a). 

REACTION:  The  black  color  in  the  melting  of  the 
impure  nitrate  comes  from  the  beginning  of  the  de- 
composition of  the  cupric  nitrate.  In  order  to  avoid 
loss  of  silver,  do  not  heat  so  long  that  all  the  copper 
salt  is  converted  into  oxide;  but  base  the  separation 
of  the  silver  from  the  copper  on  -the  fact  that  silver 
is  precipitated  in  a  metallic  form  from  an  ammoniacal 
solution  by  means  of  sulphurous  acid,  while  the  cop- 
per is,  under  these  conditions,  reduced  to  cuprous 
oxide  which  remains  in  solution  in  the  ammoniacal 
liquid,  and  the  slow  precipitation  of  the  silver  in  a 
crystalline  form  is  brought  about. 

TEST:  Dissolve  a  sample  of  the  silver  in  nitric  acid 
which  is  free  from  chlorine,  and  examine  any  residue 
there  may  -happen  to  be  (gold,  silver  chloride,  stannic 
oxide):  precipitate  a  solution  with  hydrochloric  acid, 
and  test  the  filtrate  for  heavy  metals. 


INORGANIC  CHEMICAL   PREPARATIONS.          21 

PURE  GOLD,  Au. 

Gold,  such  as  is  used  in  the  arts  (broken  pieces  of 
jewelry,  a  coin,  or  crude  gold  dust),  is  cut  up  into  as 
small  pieces  as  possible,  weighed,  and  treated  in  a  small 
flask  with  concentrated  hydrochloric  acid.  Heat  the 
small  flask  on  a  sand-bath,  and  add  concentrated  nitric 
acid  from  time  to  time.  As  soon  as  all  has  gone  into 
solution,  evaporate  on  a  water-bath,  with  the  careful 
exclusion  of  dust,  to  such  an  extent  that  the  remain- 
ing dark-red  liquid  solidifies  upon  cooling.  Then 
take  up  in  much  water,  filter  from  the  silver  chloride 
which  has  separated,  and  treat  the  filtrate  hot  with  a 
great  excess  of  ferrous  chloride.  Decant  the  pul- 
verulent gold  w'hich  separates,  heat  up  once  with 
dilute  hydrochloric  acid,  collect  on  an  ashless  filter, 
heat  in  a  porcelain  crucible,  and  weigh. 

In  case  larger  amounts  of  gold  are  separated,  a 
little  platinum  and  palladium  (also  thallium)  may  be 
obtained  from  the  filtrate  by  means  of  iron  or  zinc. 

TEST:  The  gold,  which  is  obtained  in  the  form  of 
a  reddish  powder,  should  impart  no  trace  of  a  yellow 
color  (iron)  to  boiling  concentrated  hydrochloric  acid. 
If  a  weighed  amount  is  again  subjected  to  the  proce- 
dure for  separation  described  above,  the  weight  must 
remain  absolutely  constant. 


22          INORGANIC  CHEMICAL   PREPARATIONS. 


ANHYDROUS   MAGNESIUM    CHLORIDE, 
MgCl2. 

Dissolve  500  grams  of  crystallized  magnesium 
chloride  with  500  grams  of  ammonium  chloride  in 
the  smallest  quantity  of  water,  fiker  and  evaporate  in 
a  porcelain  dish  to  dryness;  the  last  operation  being 
best  accomplished  in  a  silver  dish.  Break  up  the  solid 
mass  while  it  is  still  hot,  and  dry  in  small  portions  in 
a  porcelain  dish,  or,  better  still,  in  a  platinum  dish 
(all  the  baser  metals,  including  silver,  are  attacked 
by  this  mixture  at  higher  temperatures).  This  opera- 
tion lasts  a  long  time  and  is  to  be  carried  out  with 
special  care;  for  if  but  very  small  quantities  of  water 
remain  behind,  the  successful  result  of  the  experiment 
is  frustrated.  Utilize  several  gas-stoves  at  the  same 
time  for  the  drying,  and  regulate  the  flames  so  that 
ammonium  chloride  vapors  are  not  evolved.  Grind 
up  the  portions  from  time  to  time  in  a  hot  mortar, 
continue  the  drying  until  the  product  gives  a  powder 
which  does  not  lump -together  upon  heating;  consider 
the  operation  ended  only  when  a  sample  in  a  test- 
tube  gives  off  no  moisture  upon  heating,  and  when, 
after  driving  off  the  ammonium  chloride,  there  re- 
mains a  quite  mobile  clear  liquid  which,  upon  cooling, 
solidifies  in-. radiating  crystals.  Add  the  powder  * 

*  If  the  dried  substance  is  to  be  preserved,  this  must  be  done 


INORGANIC  CHEMICAL  PREPARATIONS.       23 

while  still  hot  to  a  large  platinum  crucible,  close  it 
with  a  well-fitting  cover,  and  place  it  in  a  Rossler 
furnace  (see  appendix)  which  has  previously  been 
heated.  After  driving  off  the  ammonium  chloride, 
take  out  the  crucible,*  fill  it  again  with  the  powder, 
and  continue  the  ignition  until  the  whole  mass  :has 
been  melted.  The  solidified  magnesium  chloride, 
which  is  easily  removed  from,  the  crucible,  is  filled 
while  still  warm  into  a  well-stoppered  bottle. 

REACTION:  Crystallized  magnesium  chloride  loses 
much  hydrochloric  acid  upon  heating;  on  the  other 
hand,  the  double  salt  (NH4)2MgCl4  is,  by  careful 
heating,  dehydrated  without  decomposition.  Upon 
igniting  this  double  salt,  anhydrous  magnesium  chlo- 
ride remains:  (NH4)2Mg€l4  =  MgCl2  +  2NH4C1. 

TEST:  The  anhydrous  magnesium  chloride  should 
form  large  radiating  crystals  of  a  silky  lustre,  not  un- 
like those  of  fused  sodium  acetate,  which-  melt  easily 
upon  heating  and  volatilize  at  a  bright  heat.  The 
vapors  decompose  aqueous  vapor  instantaneously, 
forming  hydrochloric  acid.  The  very  hydroscopic 
salt  should  dissolve  clear  in  water,  with  the  evolution 
of  heat. 

in  well-stoppered  bottles.  Before  being  used,  the  mass  is  to  be 
dried  again  for  a  short  time  on  the  gas-stove. 

*  When  the  crucible  is  at  a  bright  heat,  it  should  not  be 
opened,  on  account  of  the  volatility  of  the  magnesium  chloride. 


24         INORGANIC  CHEMICAL  PREPARATIONS. 


POROUS   CALCIUM   CHLORIDE,  CaCl2. 

Heat  i  liter  of  the  mother-liquor,  from  the  genera- 
tion of  carbon  dioxide  from  marble  and  commercial 
hydrochloric  acid,  which  no  longer  reacts  with  an 
excess  of  marble;  then  treat  it  in  a  2-liter  iron  pot 
with  milk  of  lime  (made  from  35  grams  of  lime)  and, 
after  boiling,  filter  the  strongly  alkaline  liquid.*  Add 
hydrochloric  acid  to  the  filtrate  until  strongly  acid, 
and  evaporate  in  portions  in  a  |-liter  porcelain  dish 
on  the  gas-stove  (see  appendix).  As  soon  as  a  layer 
of  salt  forms  on  the  surface,  turn  down  the  flame, 
add  some  fuming  hydrochloric  acid,  and  let  the  solu- 
tion stand  quietly  without  stirring,  so  that  the 
mass  does  not  become  fully  dry  until  after  4-5 
hours.  By  the  aid  of  a  knife,  carefully  loosen  the  por- 
ous calcium  chloride  from  the  dish,  break  up  the  large 
pieces  while  still  hot  in  a  warmed  mortar,  sort  the 
small  pieces  as  rapidly  as  possible,  according  to  the 
size  of  the  grains,  by  use  of  a  sieve  having  meshes 
from  1-5  mm.  in  diameter,  and  fill  immediately  into 
a  well-stoppered  preparation  bottle. 

REACTION:  The  lime  precipitates  the  magnesium, 
as  well  as  the  iron  and  manganese,  from  the  solution 

*  In  place  of  starting  with  this,  the  residue  of  calcium  chloride 
and  excess  of  lime  from  the  preparation  of  ammonia  may  be 
used.  Heat  this  up  with  water  until  the  last  traces  of  ammonia 
have  been  driven  off,  filter,  and  continue  the  preparation  as  de- 
scribed above. 


INORGANIC  CHEMICAL  PREPARATIONS.          2$ 

obtained  from  the  marble.  (Upon  standing,  basic 
calcium  chloride,  3CaO,CaCl2  +  isH2O,  frequently 
separates  from  the  filtrate  in  beautiful  long  prisms.) 
In  evaporating  to  dryness,  the  solution  must  be  acid 
with  hydrochloric  acid  and  the  heating  gradual,  be- 
cause otherwise  the  calcium  chloride  loses  hydro- 
chloric acid  and  reacts  strongly  alkaline. 

TEST:  The  calcium  chloride  forms  pure  white,  por- 
ous, very  -hydroscopic  pieces.  These  should  dissolve 
in  water,  and  also  in  alcohol,  to  a  clear  solution;  the 
aqueous  solution  should  .react  but  weakly  alkaline. 


CALCIUM   CARBONATE,  CaCO3. 

Purify  i-J  liters  of  calcium  chloride  mother-liquors 
with  milk  of  lime  as  described  above.  Pour  the  fil- 
trate, While  still  hot,  into  2\  liters  of  a  10%  solution 
of  commercial  ammonium  carbonate  containing  250 
c.c.  of  dilute  ammonia  (i  part  of  concentrated  am- 
monia, 2  parts  of  water).  Decant  the  thoroughly 
mixed  liquids  into  a  tall  glass  cylinder,  finally  drain 
the  precipitate  on  a  filter  by  means  of  a  pump,  and 
completely  dry  in  a  nickel  dish  on  the  gas-stove. 

REACTION: 

NH3  +  (NH4)3H(C03)2  =  2(NH4)2C08; 
CaCl2  +  (NH4)2CO3        =  CaC03  +  2NH4C1; 
Ca(OH)2  +  (NH4)2CO3  = 


26          INORGANIC  CHEMICAL   PREPARATIONS. 

TEST:  The  calcium  carbonate  is  a  snow-white, 
crystalline,  tasteless  powder,  which  dissolves  clear  in 
dilute  hydrochloric  acid,  with  strong-  effervescence. 
The  hydrochloric  acid  solution  should  give  no  pre- 
cipitate with  ammonia  (iron,  aluminium).  After  the 
precipitation  of  the  calcium  by  means  of  ammonium 
oxalate,  test  the  clear  ammoniacal  solution  for  mag- 
nesium, with  sodium  phosphate.  .A  nitric  acid  solu- 
tion must  remain  clear  upon  the  addition  of  silver 
nitrate.  The  preparation,  when  heated  in  a  small  dry 
tube,  should  give  off  neither  water  nor  ammonia. 


ZINC  FREE  FROM  ARSENIC,  Zn. 

Literature:  L.  L'Hote,  Ann.  de  chimie  et  de  physique  [6] 
3,  141;  Compt.  rend.  98,  I4QI- 

Melt  i  kilogram  of  commercial  zinc  in  a  Hessian 
crucible.  Introduce  into  the  glowing-  metal,  clear  to 
the  bottom  of  the  crucible,  pieces  of  anhydrous  mag- 
nesium chloride  (see  page  22)  and  hold  them  there 
until  they  have  gone  into  solution.  In  order  to  hold 
the  specifically  lighter  chloride  under  the  molten 
metal,  use  an  iron  wire  of  which  the  lower  part  is 
wound  into  a  compact  spiral.  Fasten  the  magnesium 
chloride  in  the  small  bell  made  in  this  manner,  by 
means  of  fine  wire,  and  then  introduce  the  wire  into 
the  metal.  After  15  grams  of  chloride  have  been 


INORGANIC  CHEMICAL   PREPARATIONS.          27 

added,  let  the  crucible  cool  to  such  an  extent  that, 
upon  uncovering  the  crucible,  the  metal  no  longer 
glows,  but  is  still  just  fluid;  then  pour  the  thinnest 
possible  stream  into  a  pail  of  water.  Take  out  the 
granulated  zinc,  drain  it,  and  dry  by  warming. 

REACTION:  3MgCl2  +  2As  =  3Mg  +  2AsCl3.  The 
arsenious  chloride  and  the  undecomposed  magnesium 
chloride  volatilize  in  thick  clouds. 

TEST:  The  zinc  obtained  in  this  way  contains  mag- 
nesium and,  consequently,  in  contrast  to  chemically 
pure  zinc,  is  very  easily  soluble  in  dilute  acids.  In 
order  to  test  it  for  arsenic,  treat  in  a  small  test-tube 
with  dilute  hydrochloric  acid  (1:1)  and  cover  the  tube 
with  a  small  filter,  the  point  of  which  is  moistened 
with  a  drop  of  concentrated  silver  nitrate  solution 
(1:1).  After  a  greater  or  less  length  of  time,  yellow 
arsenic  silver  nitrate,  Ag6As(NO3)3,  is  formed,  which 
decomposes  with  water  and  turns  black,  according  to 
the  equation: 

4Ag6As(N03)3+6H20=24Ag+As406+i2HN03. 


STRONTIUM  HYDROXIDE,  Sr(OH)2  +  8H2O. 

Pack  an  intimate  mixture  of  150  grams  of  finely 
pulverized  celestite  and  50  grams  of  charcoal  tightly 
in  a  Hessian  crucible,  and  cover  with  a  layer  of  pow- 
dered charcoal.  Close  the  crucible  with  a  well-fitting 


28          INORGANIC  CHEMICAL   PREPARATIONS. 

iron  cover  that  has  an  attached  rim,  and  heat  at  a 
white  heat  for  one  hour  in  the  Rossler  gas-furnace 
(see  appendix).  The  cooled  product  must  go  into 
solution  upon  treatment  with  dilute  hydrochloric  acid, 
with  the  strong  evolution  of  hydrogen  sulphide,  leav- 
ing but  a  small  carbonaceous  residue.  Determine 
this  point  by  a  small  test.  Suspend  the  mass  in  a 
liter  of  hot  water  in  a  porcelain  dish,  and  add  well- 
ignited  copper  scale  (100-150  grams)  to  the  boiling 
liquid,  until  a  filtered  test  no  longer  gives  a  brownish 
black  precipitate  with  lead  acetate.  Filter  hot  into  a 
beaker,  heat  up  the  residue  again  with  100  c.c.  of 
water;  carefully  cover  the  combined  nitrates,  and  let 
crystallize.  After  24  hours,  pour  off  the  liquor  from 
the  crystals  which  have  separated,  dry  these  as  rapidly 
?s  possible  on  a  covered  porous  plate,  and  put  them 
into  a  bottle  which  is  to  be  corked  and  paraffined. 
Rapidly  evaporate  the  mother-liquor  to  300  c.c.,  in 
order  to  obtain  a  second  crystallization. 

REACTION:  The  strontium  sulphate  is  converted 
into  strontium  sulphide  by  igniting  with  charcoal, 
when  the  air  is  excluded;  the  strontium  sulphide  is 
changed  to  strontium  hydroxide  by  means  of  the  cop- 
per oxide: 


SrS  +  CuO  +  H2O  =  Sr(OH)2  +  CuS. 

TEST:     Strontium    hydroxide    forms    transparent, 
efflorescent    quadratic    plates    or   needles,    having   a 


INORGANIC   CHEMICAL    PREPARATIONS.          2$ 

strong  alkaline  taste,  and  is  easily  soluble  in  hot  water 
which  has  previously  been  boiled,  leaving  no  residue. 
It  melts  easily  upon  heating,  and  upon  further  heating 
resolidifies  to  a  white  mass,  with  the  loss  of  its  8  mole- 
cules of  crystal  water.  At  a  still  higher  temperature 
it  again  melts  and  is  finally  converted  into  strontium 
oxide.  An  acetic  acid  solution  of  the  strontium  hy- 
droxide should  not  be  precipitated  by  potassium 
dichromate  (barium'),  but  the  strontium  should  be 
so  completely  removed  by  sulphuric  acid  that  am- 
monium oxalate  gives  no  precipitate  in  the  filtrate 
(calcium). 


CADMIUM  CARBONATE,  CdCO3. 

Place  100  grams  of  commercial  cadmium,  which 
has  been  cut  into  pieces  or  granulated,  in  a  flask  with 
400  c.c.  of  cold  nitric  acid  of  a  specific  gravity  of  1.2; 
leading  the  oxides  of  nitrogen,  which  are  evolved  in 
large  amounts,  into  the  flue  of  a  hood  by  means  of  an 
ascending  tube.  After  the  action  has  completely 
ceased,  pour  the  liquid  from  the  undissolved  portion 
into  a  porcelain  dish  of  6  liters  content,  dilute  with  4 
liters  of  hot  water,  and  add  commercial  ammonium 
carbonate  in  the  form  of  a  powder,  until  there  is  just  a 
small  permanent  precipitate  formed.  Filter  this  off, 
and,  by  the  addition  of  an  excess  of  ammonium  cac- 
bonate  (about  150  grams),  precipitate  the  pure 


30          INORGANIC  CHEMICAL    PREPARATIONS. 

cadmium  carbonate  from  the  filtrate.  Decant  several 
times  with  hot  water  in  a  tall  glass  cylinder,  and  pre- 
serve the  carbonate  as  a  paste  or  dry  it  upon  the  water- 
bath. 

REACTION: 

3Cd  +  8HNO3  =  3Cd(NO3)2  +  2NO  +  4H2O. 

The  metals  present  as  impurities,  with  the  excep- 
tion of  the  zinc  and  iron,  do  not  remain  in  solution, 
but  are  again  thrown  out  in  a  metallic  form  by  the 
excess  of  cadmium.  The  iron  precipitates  with  the 
first  portion  of  the  cadmium  carbonate: 

3CdC03  +  2Fe(N03)3  +  3H20 

=  3Cd(N03)2  +  2Fe(OH)3  +  3CO2. 

The  zinc  is  kept  in  solution  by  the  excess  of  the 
ammonium  salt. 

TEST:  Cadmium  carbonate  is  a  pure  white  salt, 
which  forms  brown  cadmium  oxide  upon  ignition  and 
dissolves  readily,  with  effervescence,  in  dilute  acids. 
It  is  to  be  especially  tested  for  antimony,  bismuth, 
copper,  lead,  iron,  and  zinc,  according  to  the  cus- 
tomary methods  of  analysis. 


BARIUM   OXIDE,  BaO. 

Reduce  150  grams  of  heavy  spar  with  40  grams 
of  charcoals-according  to  the  method  described  for 
celestite  (page  27),  and  decompose  the  barium 


INORGANIC   CHEMICAL   PREPARATIONS.          31 

sulphide  thus  obtained,  in  a  liter  flask  by  means  of 
dilute  nitric  acid,  the  flask  being  fitted  with  a  drop- 
funnel  and  a  tube  for  conducting  away  the  gases 
evolved.  Filter  the  solution  and  evaporate  to  crys- 
tallization. Add  ij  kilograms  of  the  salt  thus 
obtained,  or  commercial  barium  nitrate,  gradually,  by 
means  of  an  iron  spoon,  to  a  white-hot  Hessian  cruci- 
ble which  is  kept  covered  with  a  fire-clay  cover  that 
fits  as  well  as  possible.  After  the  final  addition,  heat 
the  closed  crucible  for  an  hour  at  the  highest  possible 
temperature.  After  it  is  partially  cooled,  remove  the 
upper  layer,  which  is  colored  green  (principally 
through  the  presence  of  barium  manganate),  and  fill 
the  barium  oxide  immediately  into  a  small  flask 
which  is  closed  by  being  sealed  off. 

REACTION:  Upon  ignition,  barium  nitrate  is  con- 
verted first  of  all  into  barium  nitrite  and  then  into 
barium  oxide: 

Ba(N03)2  =  Ba(N02)2  +  20; 
Ba(NO2)2  =  BaO  +  2N  +  3O. 

TEST:  Barium  oxide  forms  grayish-white  porous 
pieces  that  heat  up  with  water  and  dissolve  clear  in 
dilute  acids  without  effervescing.  This  solution 
should  not  decolorize  permanganate,  or  turn  potas- 
sium iodide  and  starch  paper  blue  (barium  nitrite  and 
barium  peroxide). 


32          INORGANIC    CHEMICAL   PREPARATIONS. 

BARIUM    HYDROXIDE,   Ba(OH)2  +  8H2O. 

This  preparation  may  be  made  from  barium  sul- 
phide, according  to  the  method  given  for  strontium 
hydroxide,  or  in  the  following  way: 

Dissolve  I  kilogram  of  barium  chloride  in  2.  liters  of 
hot  water,  add  1115  grams  of  sodium  hydroxide  solu- 
tion of  33°  Be.  (or  specific  gravity  1.29),*  filter,  and 
set  aside  to  crystallize.  From  hot  water  twice  recrys- 
tallize  the  barium  hydroxide,  which  is  filtered  off  on  a 
platinum  cone  by  means  of  a  water  vacuum  pump, 
and  dry  and  preserve  in  the  same  way  as  the  strontium 
hydroxide. 

REACTION: 

BaQ2  +  2NaOH  ==  Ba(OH)2  +  2NaCl. 

TEST:  The  barium  is  completely  precipitated  from 
an  acetic  acid  solution  t  by  the  addition  of  potassium 
dichromate.  The  filtrate,  the  color  of  which  must  be 
somewhat  darker  yellow  than  that  of  the  barium 
chromate,  should  be  precipitated  neither  by  ammo- 
nium oxalate  (calcium)  nor  by  dilute  sulphuric  acid 
upon  long  standing  (strontium). 

*  To  prepare  this,  dissolve  310  grams  of  commercial  sodium 
hydrate  in  840  grams  of  water. — See  also  pages  4  and  5. 


INORGANIC  CHEMICAL   PREPARATIONS.  33 

BARIUM   PEROXIDE,   BaO2; 

HYDRATED   BARIUM   PEROXIDE, 
Ba(OH)4  +  6H20. 

(1)  Place  30  grams  of  barium  oxide  in  a  hard  glass 
tube,  and  heat  moderately  in  a  combustion -furnace, 
in  a  strong  current  of  oxygen  which  has  been  dried 
by  concentrated  sulphuric  acid.     Add  the  peroxide, 
which  has  been  cooled  and  ground  up  with  a  little 
water,  to  50  c.c.  of  dilute  hydrochloric  acid  which  is 
cooled  to  o°.    Filter  the  still  weakly  acid  solution,  and 
add  it  to  500  c.c.  of  saturated  barium  hydrate  solution 
which  is  cooled  to  o°.     Filter  the  precipitate,  which 
consists  of  small  shining  crystalline  leaflets,  wash  with 
ice-water,  and  preserve  as  a  paste. 

(2)  Cool  \  liter  of  commercial  hydrogen  peroxide 
in  a  flask  to  o°,  and  treat  with  a  cold  saturated  barium 
hydrate  solution  until  there  is  formed  a  small  precipi- 
tate which  does  not  dissolve  and  the  solution  is  alka- 
line.   Cool  the  filtered  solution  further  and  pour,  with 
constant  stirring,  into  2  liters  of  ice-cold  barium  hy- 
drate  solution.      When   the   shining  crystalline   pre- 
cipitate does  not  increase  any  more  in  bulk,  filter  off 
the  hydrated  barium  peroxide  and  wash  with  a  little 
ice-wrater. 

REACTION:  At  a  moderate  heat,  barium  oxide  adds 
another  atom  of  oxygen.  Barium  peroxide  is  de- 
composed by  hydrochloric  acid: 

BaO2  +  2HC1  =  BaCl2  +  H2O2; 


34          INORGANIC  CHEMICAL   PREPARATIONS. 

the  hydrogen  peroxide  and  barium  hydroxide  react 
as  follows: 

H2O2  +  Ba(OH)2  =  Ba(OH)4. 

TEST:  Upon  triturating  with  water,  barium  perox- 
ide should  not  heat  up,  showing  the  absence  of  barium 
oxide).  The  quality  of  the  hydrated  peroxide  is  shown 
if  hydrogen  peroxide  is  made  from  it,  according  to  the 
method  on  page  78. 


DISTILLED  MERCURY,  Hg. 

Literature:    H.  N.  Morse,  American  Chemical  Journal  7,  60. 

In  a  combustion  furnace,  one  end  of  which  is 
15  mm.  higher  than  the  other,  place  a  hard  glass  tube, 
both  ends  of  which  are  bent  downwards  as  illustrated 
in  Figure  i.  One  end  of  the  tube,  which  is  drawn  out, 
is  attached  to  a  fairly  thick-walled  glass  tube,  of  about 
10  mm.  outside  diameter,  by  means  of  a  rubber  con- 
nection of  pressure  tubing,  the  end  of  the  glass  tube 
dipping  into  a  narrow  glass  cylinder.  The  length  of 
the  glass  tube  is  such  that  the  total  vertical  height,  up 
to  the  opening  of  the  tube  where  it  begins  to  slant 
upwards,  is  about  700  mm.  The  other  end  of  the 
combustion  tube  is  bent  somewhat  upward  within  the 
furnace,  so  that  the  last  flame  of  the  furnace  stands 
under  the  highest  portion  of  the  tube.*  From  this 

*  Place  in  this  part  of  the  tube  a  loose  plug  of  asbestos. 


INORGANIC  CHEMICAL   PREPARATIONS. 


35 


point  the  tube  extends  downwards  for  20  cm.  without 
being  contracted;   into  this  end  of  it  is  introduced  a 


FIGURE  i. — Distillation  of  Mercury  in  Vacuo. 

second  glass  tube,  which,  like  the  tube  attached  at 
the  other  end,  is  bent  into  a  hook  at  the  bottom,  being 
held  in  position  by  means  of  a  piece  of  rubber  tubing.* 
At  least  5  cm.  of  the  tube,  which  is  introduced  into 
the  wider  one,  is  free,  its  total  length  being  about 
80  cm.  In  order  to  start  the  furnace,  pour  into  the 
cylinder  commercial  mercury,  or  mercury  which,  on 

*  In  order  to  be  surer  of  a  completely  air-tight  joint  at  this 
place,  utilize  the  arrangement  as  drawn  in  Figure  2.  This  de- 
vice, which  surrounds  the  inner  tube,  is  made  by  means  of  a 
rubber  stopper  and  a  small  piece  of  large  glass  tubing,  the  cup 
formed  being  filled  with  mercury. 


INORGANIC   CHEMICAL   PREPARATIONS. 


account  of  its  use  with  others  metals,  has  become 
impure.  Exhaust  the  air  by  means  of  a  good  water 
vacuum  pump,  placing  an  empty  Woulff  bottle  be- 
tween the  apparatus  and  the  pump.  When  the  mer- 
cury has  risen  high  enough  to  form  a  layer  of  the 
liquid  throughout  the  length  of  that  part  of  the  com- 


FIGURE  2. — Air-tight  Mercury  Trap. 

bustion  tube  lying  within  the  furnace,  the  tube  leading 
to  the  pump  is  closed  with  a  pinch-cock.  Heat  the 
combustion  tube  with  a  small  flame,  so  that  the  mer- 
cury just  barely  boils  and  distils  through  the  asbestos 
plug.  As  soon  as  the  descending  tube  is  half-filled 
with  mercury,  let  the  air  carefully  into  the  pressure 
tubing  by  opening  the  pinch-cock,  and  remove  the 
pressure  tubing;  for  the  mercury  column  prevents 
the  entrance  of  air  into  this  side  of  the  apparatus.  The 
apparatus  now  works  automatically  and  the  distilled 
mercury  falls  continuously  into  a  receiver,  if  the  req- 
uisite amount  of  mercury  is  placed  in  the  cylinder 
from  time  to  time. 


INORGANIC  CHEMICAL  PREPARATIONS.          37 

TEST:  Mercury  should  have  the  specific  gravity  of 
13.595  at  °°>  and  be  °f  a  Pure  silvery  lustre;  it  should 
be  mobile  and  form,  upon  being-  poured  out,  only 
spherical  drops,  leaving  no  oblong,  thread-like  residue 
of.  a  more  viscous  character.  Five  grams  heated  in  a 
porcelain  crucible  must  leave  no  weighable  residue 
after  ignition. 


MERCURIC  CHLORIDE,    HgCl2  (from  mercury 
residues). 

Subject  residues,  which  have  been  oxidized  with 
commercial  hydrochloric  and  nitric  acids  and  evapo- 
rated to  dryness  on  a  water-bath  in  a  porcelain  dish 
covered  with  a  large  funnel,  to  a  slow  sublimation  on 
a  bath  of  sand  or  iron  filings.  According  to  its  purity, 
dissolve  Vio  to  1/5  of  this  sublimate  in  hot  water,  pre- 
cipitate with  sodium  hydrate,  and,  after  washing  and 
drying  the  precipitate,  grind,  with  the  main  portion 
of  the  sublimate,  the  mercuric  oxide  thus  obtained. 
Place  in  a  flask  the  resultant  powder,  which  is  black- 
ened by  the  formation  of  mercuric  oxychloride,  cover 
loosely  with  a  watch-glass,  and  heat  with  a  small  flame 
on  a  bath  of  iron  filings.  The  sublimate  deposits  in 
the  upper  portion  of  the  flask  in  very  beautiful  long 
crystals.  When  the  sublimation  is  finished,  take  the 
flask  from  the  bath,  crack  the  bottom  of  it  by  passing 
a  moist  sponge  rapidly  over  it,  and  separate  the  crys- 


38          INORGANIC  CHEMICAL   PREPARATIONS. 

tals  from  the  glass,  on  a  large  sheet  of  paper,  by  means 
of  a  feather.  If  less  well-crystallized  portions  are  also 
found,  these  are  recrystallized  from  4  parts  of  boiling 
water. 

REACTION:  The  crude  sublimate  is  contaminated 
by  other  volatile  metallic  chlorides,  which  are  all  de- 
composed by  mercuric  oxide;  for  example: 

2FeQ3  +  3HgO  s=  Fe203  +  3HgCl2. 

TEST:  Mercuric  chloride  forms  snow-white,  rhom- 
bic prisms,  which  are  easily  soluble  in  cold  alcohol 
and  ether,  also  in  hot  water,  leaving  no  residue 
(calomel,  ferric  oxide,  etc.),  and  which  completely 
volatilize  upon  heating  in  a  test-tube. 


MERCURIC  CYANIDE,  Hg(CN)2. 

Treat  a  dilute  solution  of  hydrocyanic  acid  (see 
page  62)  in  a  flask  with  yellow  mercuric  oxide,  until 
the  solution  reacts  strongly  alkaline  to  litmus  paper. 
Add  sufficient  hydrocyanic  acid  to  the  filtrate,  so  that 
it  gives  off  the  odor  of  it  and  reacts  distinctly  acid; 
then  evaporate  to  crystallization.  Before  again 
evaporating  the  mother-liquor  to  crystallization,  add 
some  more  hydrocyanic  acid. 

TEST:  Mercuric  cyanide  is  soluble  in  u  parts  of 
cold  water",  reacts  neutral,  and  forms  quadratic  col- 
umns and  pyramids  which  have  an  unpleasant  metallic 


INORGANIC  CHEMICAL  PREPARATIONS.          39 

taste.  On  heating  in  a  small  tube,  the  salt  evolves 
cyanogen,  forms  a  sublimate  of  small  drops  of 
mercury,  and  leaves  a  black  residue  of  paracyanogen. 


MERCURIC    SULPHIDE,    HgS. 

Grind  60  grams  of  mercury  and  23  grams  of  flowers 
of  sulphur  together  in  a  mortar,  until  no  more  mer- 
cury is  to  be  seen;  treat  with  a  solution  of  15  grams 
of  potassium  hydrate  in  80  c.c.  of  water,  and  digest 
at  about  45°  for  several  days,  stirring  frequently  and 
replacing  the  water  lost  by  evaporation.  When  the 
mass  has  become  red,  it  is  separated  by  levigation 
from  the  unchanged  mercury  and  the  greater  part  of 
the  sulphur,  heated  with  a  sodium  sulphite  solution, 
filtered,  and  washed  with  hot  water.  About  40  grams 
of  mercuric  sulphide  are  obtained. 

TEST:  Mercuric  sulphide  is  a  scarlet-red  powder 
which,  on  strongly  heating  in  a  small  tube,  completely 
volatilizes,  leaving  no  residue. 


BORON,   B. 

Literature:  Erdmann,  Lehrbuch  der  anorganischen  Chemie, 
page  403. 

Mix  thoroughly,  while  still  warm,  100  grams  of 
borax,  which  has  been  melted  and  then  finely  pow- 
dered, with  50  grams  of  magnesium  powder;  place 


40          INORGANIC   CHEMICAL   PREPARATIONS. 

the  mass  in  a  Hessian  crucible,  pack  tightly,  and  cover 
with  a  layer  of  pure  borax.  All  these  operations  must 
be  carried  out  as  rapidly  as  possible,  using  warm 
apparatus;  for  the  dehydrated  borax  is  very  hydro- 
scopic.  Close  the  apparatus  with  a  specially  con- 
structed well-fitting  cover  which  is  made  of  sheet 
iron  and  has  a  flange  fitting  over  the  outside  of  the 
crucible;  heat  in  a  Rossler  furnace  (see  appendix)  for 
a  quarter  of  an  hour  at  a  red  heat.  After  cooling,  pul- 
verize the  product  of  the  reaction,  heat  with  water, 
then  with  hydrochloric  acid,  and  finally  again  with 
water;  and  dry  the  resulting  gray-brown  powder  on 
the  water-bath. 


BORIC  ACID,  H3BO3. 

Dissolve  200  grams  of  pulverized  borax  in  \  liter 
of  boiling  water,  and  add  300  c.c.  of  dilute  hydro- 
chloric acid.  After  a  few  days,  filter,  on  a  platinum 
cone,  the  flaky  crystals  which  separate,  wash  them 
with  a  very  little  water  and  recrystallize  from  water. 

TES*T:  The  white  crystals,  which  have  a  mother-of- 
pearl  lustre,  should  dissolve  in  6  parts  of  alcohol  and 
25  parts  of  cold  water.  They  should  melt  upon  heat- 
ing, with  loss  of  water,  to  a  colorless  bead,  which, 
upon  cooling,  forms  a  transparent  glass-like  mass. 
The  aqueous  solution  reddens  litmus  paper;  and  if 
strips  of  turmeric-paper  are  saturated  with  this  solu- 


INORGANIC  CHEMICAL   PREPARATIONS.          41 

tion  and  dried  in  a  warm  place,  the  yellow  dyestuff 
is  changed  to  an  orange-brown,  the  latter  color 
changing  to  green-black  with  alkalies.  Of  impurities, 
hydrochloric  acid  and  sulphuric  acid  are  particularly 
to  be  tested  for. 


AMMONIUM   PERBORATE,   NH4BO3  +  iH2O. 

Literature:  Melikoff  and  Pissarjewsky,  Berichte  d.  d.  chem. 
Ges.  31,  953;  Zeitschr.  anorgan.  Chem.  18,  62. 

Add  to  500  c.c.  of  a  3%  hydrogen  peroxide  solution, 
which  is  cooled  externally  with  ice-water,  25  grams 
of  finely  pulverized  boric  acid,  the  content  of  the 
hydrogen  peroxide  solution  having  been  determined, 
shortly  before  its  use,  by  titration  with  perman- 
ganate (see  page*  80).  After  the  acid  has  gone  into 
solution,  make  the  solution  alkaline  with  30  c.c.  of 
concentrated  ammonia  (specific  gravity  0.89)  and  pre- 
cipitate the  ammonium  perborate  by  the  addition  of 
-i  liter  of  alcohol.  Filter  off  the  white  crystals  and 
dry  them  in  vacuo  over  sulphuric  acid.  In  a  freshly 
precipitated  condition,  the  salt  contains  3  molecules 
of  water  of  crystallization;  but  after  standing  one  day 
over  sulphuric  acid,  this  unstable  salt,  which  is  rich  in 
water,  goes  over  into- the  more  stable  compound 

NH4B03  +  iH20      or     (NH4)2H2B2O7 
(analogous  to  sodium  metantimonate,  Na2H2SbO7). 


42          INORGANIC  CHEMICAL  PREPARATIONS. 

TEST:  Treat  0.15  gram  of  the  salt  in  a  test-tube  with 
5  c.c.  of  lukewarm  water.  The  salt  dissolves  slowly, 
giving  off -the  odor  of  ammonia  and  evolving  oxygen; 
ammonium  nitrite  is  formed  at  the  same  time.  A  solu- 
tion of  the  ammonium  perborate  acidified  with  sul- 
phuric acid,  turns  potassium  iodide  and  starch  paper 
blue;  it  contains  hydrogen  peroxide  and  decomposes 
very  rapidly.  The  salt  evolves  chlorine  with  hydro- 
chloric acid,  and  ozone  with  concentrated  sulphuric 
acid. 


ALUMINIUM   HYDROXIDE,   A1(OH)3 
(from  cryolite). 

Finely  pulverize  50  grams  of  cryolite,  mix  in- 
timately with  50  grams  of  lime  made  from  marble, 
and  ignite  strongly  in  a  platinum  crucible  for  half  an 
hour  in  a  Rossler  furnace  (see  appendix).  Heat  the 
pulverized  frit  with  water;  remove  the  traces  of  lime 
that  may  happen  to  be  present  in  the  filtrate,  by  means 
of  a  few  drops  of  sodium  carbonate  solution;  and  then 
precipitate  the  solution  hot,  by  means  of  carbon  diox- 
ide. Decant,  with  much  hot  water,  the  aluminium  hy- 
droxide which  separates,  drain,  bring  to  dryness  on 
the  water-bath,  and,  if  desirable,  convert  into  anhy- 
drous aluminium  oxide  by  ignition.  By  evaporating 
the  filtrate,  pure  sodium  carbonate  is  obtained. 


INORGANIC  CHEMICAL  PREPARATIONS.         43 

REACTION:  The  sodium  aluminium  fluoride  is  de- 
composed by  the  lime,  forming  sodium  aluminate, 
which  is  soluble  in  water: 

Na3AlF6  +  3CaO  =  Na3AlO3  +  3CaF2. 

The  sodium  aluminate  is  decomposed  by  the  carbonic 
acid: 

2Na3A103  +  3H2C08  -  2H3A1O3  +  3Na2CO3. 


ANHYDROUS   ALUMINIUM    CHLORIDE, 

A1C13. 

Wash  50  grams  of  aluminium  turnings  with  alcohol 
and  ether,  dry  them,  and  gently  heat  them  in  a  retort 
in  a  stream  of  dry  chlorine.  The  chloride  condenses 
in  the  neck  of  the  retort  in  colorless  hexagonal  plates, 
or  as  a  compact  laminated  mass. 

REACTION:    Al  +  3C1  =  A1C13. 

Anhydrous  aluminium  chloride  is  an  exceptionally 
reactive  substance,  which  gives  compounds  with  the 
alkaline  chlorides,  ammonia,  hydrogen  phosphide,  sul- 
phur dioxide,  and  the  chlorides  and  oxychlorides  of 
phosphorus,  nitrogen,  and  sulphur,  as  well  as  with 
many  hydrocarbons.  It  serves  in  organic  synthesis 
as  an  energetic  agent  for  producing  condensations. 

TEST:  Aluminium  chloride  fumes  in  the  air,  is  de- 
composed immediately  by  the  moisture  of  the  air  into 
aluminium  hydroxide  and  hydrochloric  acid  gas,  and 


44          INORGANIC   CHEMICAL   PREPARATIONS. 

dissolves  in  water  with  a  hissing  noise  and  the  produc- 
tion of  much  heat,  the  same  phenomena  as  in  the  case 
of  phosphorus  pentac'hloride.  It  is  not  known  what 
chemical  changes  take  place  under  these  circum- 
stances. Upon  cooling  or  evaporating  in  vacuo, 
columnar  crystals  of  an  unknown  constitution  are 
obtained,  which  have  the  empirical  constitution 
A1C13  +  6H2O.  Upon  heating,  these  crystals  do  not 
break  down  into  water  and  aluminium  chloride,  but 
into  hydrochloric  acid,  water,  and  aluminium  hy- 
droxide. 

PURE   OXALIC  ACID,   H2C2O4  +  2H2O. 

Treat  i  kilogram  of  commercial  oxalic  acid  with 
700  c.c.  of  hot  water,  and  heat  for  a  few  minutes. 
Pour  off  from  the  undissolved  portion,  and  add  300 
c.c.  of  fuming  hydrochloric  acid  to  the  liquid.  After 
the  acid,  which  separates  upon  cooling,  has  been 
washed  with  a  very  little  cold  water,  recrystallize  it 
from  boiling  water. 

REACTION:  The  oxalates  mixed  with  the  com- 
mercial oxalic  acid  are  less  soluble  than  it,  and,  for 
the  most  part,  remain  undissolved  upon  treatment 
with  an  insufficient  amount  of  water.  The  rest  of  the 
compounds  are  decomposed  by  the  strong  acid. 

TEST:  5  grams  of  this  preparation,  volatilized  in 
a  weighed  platinum  dish,  should  leave  no  weighable 
residue. 


INORGANIC  CHEMICAL   PREPARATIONS.          45 

ANHYDROUS  OXALIC  ACID,  H2C2O4. 

Divide  500  grams  of  commercial  oxalic  acid  among 
a  large  number  of  pasteboard  boxes,  spread  out  the 
acid  in  thin  layers  in  them,  and  dry  in  a  steam-drying 
closet,  whereby  the  portion  of  the  paper  in  contact 
with  the  anhydrous  acid  is  partially  carbonized.  Sub- 
lime the  crystals,  which  have  completely  crumbled, 
on  a  sand-bath  at  150-160°.  The  anhydrous  oxalic 
acid  forms  very  long,  white,  completely  ashless  crys- 
tals, which  take  up  moisture  rapidly  from  the  air  and 
consequently  increase  considerably  in  weight.  Upon 
warming,  organic  chlorides  are  energetically  decom- 
,  posed  by  anhydrous  oxalic  acid,  with  the  splitting  off 
of  hydrochloric  acid;  benzalchloride  thus  produces 
benzaldehyde : 

C6H5CHC12  "T  H2C2O4 

=  C6H5CHO  +  2HC1  +  CO  +  CO2. 


ETHYL   BROMIDE,    C2H5Br. 

Literature:    Erdmann,  Chemische  Pfaparatenkunde  (Stuttgart 
1894)  Bd.  II,  37- 

Quickly  add  218  c.c.  of  sulphuric  acid  of  a  specific 
gravity  of  1.835,  to  2I&  c.c.  of  96%  alcohol  in  a  dish, 
stirring  rapidly  during  the  addition.  After  cooling, 
add  150  c.c.  of  ice-water,  stirring  carefully;  then  add 
the  mixture  to  200  grams  of  potassium  bromide  in 


46          INORGANIC  CHEMICAL   PREPARATIONS. 

a  2-liter  flask.  Fit  the  flask  with  a  three-hole  rubber 
stopper,  carrying  an  ascending  tube,  thermometer, 
and  a  bent  tube  connected  with  a  condenser.  The 
condenser  discharges  into  an  adapter,  which  dips  ver- 
tically into  a  receiver  containing  some  water.  The  re- 
action is  started  by  heating  slowly  on  the  gas-stove.  It 
takes  place  mostly  between  90°  and  110°,  but  at  the 
end  the  temperature  must  be  raised  to  125°.  Separate 
carefully  from  the  water  the  ethyl  bromide  thus  ob- 
tained, cool  in  a  cooling  mixture,  and  add  concen- 
trated sulphuric  acid,  drop  by  drop,  until  the  acid 
layer  falls  to  the  bottom  as  a  heavy  oil.  After  remov- 
ing the  sulphuric  acid,  which  takes  up  the  ethyl  ether 
mixed  with  the  ethyl  bromide,  wash  with  water,  dry 
over  calcium  chloride,  and  rectify  on  the  water-bath. 
Catch  the  very  volatile  distillate  in  a  receiver  cooled 
by  ice.  Yield,  about  150  grams. 

REACTION:  Ethyl  sulphuric  acid  is  formed  by  the 
rapid  mixing  of  the  alcohol  and  sulphuric  acid,  much 
heat  being  evolved: 

C2H5OH  +  H2SO4  =  C2H5O.SO3H  +  H2O. 

This  is  decomposed  by  the  potassium  bromide,  form- 
ing potassium  ethyl  sulphate,  according  to  the  equa- 
tion: 

C2HBO.SO3H  +  KBr  =  C2H5O.SO3K  +  HBr; 

but  this  salt  is  broken  up  by  the  hydrobromic  acid 
which  is  formed: 

CHO.S0K  +  HBr  =  C2H5Br  +  HO.SO3K. 


INORGANIC  CHEMICAL   PREPARATIONS.  47 

The  addition  of  water,  as  described,  is  very  im- 
portant for  the  success  of  the  operation;  for,  if 
omitted,  the  hydrobromic  acid  is  evolved  as  a  gas 
before  it  can  enter  into  the  reaction  and  much  ethyl 
ether  is  formed. 

TEST:  The  preparation  should  react  neutral,  have 
a  boiling-point  of  38-39°,  and  a  specific  gravity  of 
1.476.  If  a  smaller  specific  gravity  is  observed,  the 
product  contains  ethyl  ether,  which  is  removed  by 
shaking  out  again  with  a  half  to  an  equal  volume  of 
concentrated  sulphuric  acid.  The  odor  is  quite  pleas- 
ant, refreshing,  and  fruity;  and  upon  rubbing  the 
liquid  between  the  hands,  there  should  be  left  no  trace 
of  a  less  pleasant,  or  garlic-like  odor.  The  product 
which  is  bought,  is  frequently  made  by  means  of  com- 
mercial phosphorus,  and  contains,  consequently,  vola- 
tile arsenic  compounds!  that  may  occasion  poisoning. 
Examine  the  commercial  ethyl  bromide  by  burning 
a  few  cubic  centimeters  in  a  small  spirit-lamp,  aspirat- 
ing the  products  of  combustion  through  sodium  hy- 
droxide, and  testing  the  latter  for  arsenic  by  means  of 
stannous  chloride  and  hydrochloric  acid. 


CRYSTALLINE  SILICON,  Si. 

Literature:    Erdmann,   Lehrbuch  der  anorganischen   Chemie 
(Braunschweig  1898),  pages  484  and  495. 

Mix  50  grams  of  dry  magnesium  powder  with  200 
grams  of  very  dry  sea-sand  (fine  round-grained  quartz 


48  INORGANIC  CHEMICAL   PREPARATIONS. 

sand),  and  divide  the  mixture  among  5  test-tubes. 
The  tubes  are  held  successively  in  an  iron  clamp  and 
heated  with  a  blast-lamp,  beginning  at  the  base  and 
heating  upward.  Heat  until  each  portion  has  reacted, 
as  shown  by  its  glowing.  Pulverize  the  impure 
amorphous  silicon  thus  obtained,*  and  heat  with  ten 
times  its  weight  of  zinc,  in  a  Hessian  crucible,  until 
the  zinc  just  begins  to  volatilize.  Wash  the  zinc 
regulus  with  water  and  dissolve  in.  hydrochloric  acid, 
whereupon  the  silicon 'remains  as  dark,  shining,  regu- 
lar crystals.  Wa"sh  the  crystals  with  water,  warm  with 
nitric  acid,  and  finally  heat  with'  water  again. 

REACTION:  SiO2  +  2Mg  =  Si  +  2MgO.  The  sili- 
con is  crystallized  from  the  molten  zinc,  leaving  the 
admixture  of  magnesia  undissolved. 


SILICON  TETRACHLORIDE,  SiQ4. 

Fill  a  hard  glass  tube  of  2  cm.  diameter  half  full  of  the 
impure  amorphous  silicon  which  contains  magnesia, 
as  prepared  above;  place  horizontally  in  a  combustion 
furnace,  and,  while  gently  heated,  conduct  a  stream 
of  dry  chlorine  through  it.  Condense  the  silicon 
tetrachloride  which  distils  over,  in  a  receiver  sur- 
rounded with  a  cooling  mixture  of  ice  and  oalt,  and 

*  The  fragments  of  the  test-tubes  are  to  be  freed  immediately 
from  the  ma'gnesium  silicide  present  (from  which  there  is 
danger  of  fire),  by  treating  with  hydrochloric  acid. 


INORGANIC  CHEMICAL   PREPARATIONS.          49 

take  up  the  excess  of  chlorine  in  sodium  hydrate. 
Shake  the  greenish  liquid  with  mercury  and  distil 
on  a  water-bath,  using  a  condenser;  and  have  the 
bulb  of  the  thermometer  immersed  in  the  liquid. 

REACTION:  Si  +  4C1  =  SiQ4.  The  free  chlorine 
dissolved  in  the  silicon  tetrachloride  is  taken  up  by 
the  mercury  upon  shaking. 

TEST:  Silicon  tetrachloride  should  boil  at  58-60° 
and  form  a  colorless,  quite  mobile  liquid,  which  fumes 
strongly  in  the  air  and  which  decomposes  immedi- 
ately with  water,  forming  orthosilicic  acid: 

SiQ4  +  4H2O  =  Si(OH)4  +  4HC1. 


ANHYDROUS  STANNOUS  CHLORIDE,  SnCl2. 

Heat  commercial  stannous  chlorid'e  slowly  on  the 
gas-stove;  .the  salt  melts  in  its  water  of  crystalliza- 
tion, becomes  pasty,  and  gradually  solidifies.  At  the 
end  of  the  operation,  remelt  the  dehydrated  salt. 
After  cooling,  put  it  into  a  retort  of  difficultly  fusible 
glass,  the  upper  part  of  which,  to  avoid  too  much 
radiation,  is  provided  with  a  hood  of  wire  netting  or 
asbestos.  Distil  as  rapidly  as  possible  into  a  porcelain 
dish  which  is  kept  covered  with  another  one.  As  the 
stannous  chloride  begins  to  boil  at  610°,  the  heating 
must  be  very  strong;  and  as  a  source  of  heat,  it  is 
best  to  use  a  small  blast-flame.  Heat  the  neck  of  the 


5O          INORGANIC  CHEMICAL   PREPARATIONS. 

retort  with  a  Bunsen  burner,  in  order  that  the  neck 
may  not  become  stopped  up  with  the  solidified  chlo- 
ride. 

TEST:  Stannous  chloride  is  a  white  crystalline  body 
which  melts  at  250°  and  is  easily  soluble  in  water, 
alcohol,  ether,  and  sodium  hydrate. 


ANHYDROUS    STANNIC    CHLORIDE,    SnCl4. 

Spiritus  fumans  Labavii. 

Literature:  Lorenz,  Zeitschr.  anorgan.  Chem.  10,  44;  Erd- 
mann,  Lehrbuch  der  anorganischen  Chemie,  page  658. 

For  the  preparation  of  stannic  chloride,  use  the 
apparatus  illustrated  in  Figure  3.  Fill  with  dry  granu- 
lated tin  the  tube  A,  which  is  6  cm.  wide  and  100  cm. 
high,  to  a;  add  a  small  amount  of  stannic  chloride 
(to  b),  and  then  pass  in  chlorine,  which  is  dried  by 
means  of  concentrated  sulphuric  acid.*  The  chlorine 
is  readily  absorbed  by  the  tin  tetrachloride,  the  liquid 
soon  turning  yellowish-green;  then  the  action  upon 
the  metal  begins  with  spontaneous  heating,  the  volume 
of  the  liquid  rapidly  increases,  while  the  pieces  of 
granulated  tin  assume  a  corroded  appearance  and 
finally  mat  together.  When  all  the  tin  changes  to 
chloride,  rectify  over  tin-foil  in  a  fractioning  flask,  hav- 

*  Relative  to  the  evolution  of  chlorine  and  the  absorption  of 
the  gases  which  are  evolved,  see  the  appendix. 


INORGANIC  CHEMICAL   PREPARATIONS.  5  I 

ing  the  bulb  of  the  thermometer  immersed  in  the 
liquid. 


ci 


FIGURE  3. — Preparation  of  Anhydrous  Stannic  Chloride. 

REACTION:  Sn  +  40  —  SnQ4.  The  free  chlorine 
present  is  taken  up  during  the  fractioning  by  the 
metal  which  has  been  added. 


52  INORGANIC  CHEMICAL   PREPARATIONS. 

TEST:  Stannic  chloride  is  a  colorless  liquid  which 
fumes  strongly  in  the  air,  boils  at  114°,  and  has  a 
specific  gravity  of  2.278  at  o°.  It  is  easily  soluble  in 
organic  liquids  (oil  of  turpentine,  carbon  disulphide). 
Stannic  chloride  also  dissolves  clear  in  water,  with 
contraction  and  evolution  of  much  heat,  if  too  little 
of  the  solvent  is  not  used.  Upon  mixing  with  a  small, 
measured  amount  of  water,  a  whole  series  of  hydrates 
is  formed;  with  hydrochloric  acid,  chlorostannic  acid, 
H2SnCl6,  is  obtained,  crystallizing  in  plates  which 
melt  at  28°  and  contain  6  molecules  of  water.  The 
ammonium  salt,  (NH4)2SnG6,  is  found  in  commerce 
under  the  name  of  pink  salt.  Tin  tetrachloride  forms 
crystalline  compounds  also  with  nitrous  anhydride, 
with  the  chlorides  of  phosphorus  and  sulphur,  as  well 
as  with  hydrocyanic  acid. 


LEAD  PEROXIDE,   PbO2. 
(a)  In  a  Dry  Way. 

Literature:    Kassner,  Chemische  Industrie  13,  104,  120. 

Mix  53  grams  of  lead  oxide  (see  page  6)  and  50 
grams  of  calcium  carbonate  intimately  in  a  mortar. 
Loosely  pack  a  fire-clay  crucible  with  this  mixture, 
using  a  crucible  which  is  not  very  deep  but  which  is 
as  wide  as  possible.  Ignite  in  a  Rossler  gas-furnace 
for  J  hour,  being  careful  to  have  an  excess  of  air  in 


INORGANIC  CHEMICAL   PREPARATIONS.  53 

the  space  about  the  crucible  by  diminishing  the 
amount  of  gas  used,  completely  opening  the  air  regu- 
lator, and  using  a  large  flame  in  the  flue.  After  cool- 
ing, pulverize  the  frit  (which  has  caked  but  slightly) 
in  a  mortar,  and  ignite  again  for  \  hour  at  a  bright 
red  heat.  Treat  a  pulverized  sample  of  the  product 
thus  obtained  with  dilute  nitric  acid:  if  carbon  dioxide 
is  evolved,  heat  the  pulverized  mass  again  for  a  short 
time  at  a  low  white  heat.*  Gradually  add  the  finely 
pulverized,  flesh-colored  calcium  plumbate  to  200  c.c. 
of  dilute  nitric  acid;  after  settling,  decant  and  grind 
up  in  a  mortar  with  fresh  nitric  acid  (100  c.c.).  Fi- 
nally, heat  up  with  100  c.c.  of  dilute  nitric  acid,  filter, 
wash  with  hot  water,  and  dry  on  the  water-bath.  For 
most  purposes,  it  is  more  convenient  to  wash  the  per- 
oxide by  decantation  with  hot  water  and  preserve  as 
a  paste.  The  weight  of  the  lead  peroxide  obtained  is 
about  the  same  as  that  of  the  lead  oxide  used. 


*  The  oxidation  is  accomplished  very  rapidly  it  the  mixture 
is  heated  in  a  fire-clay  crucible  (iron  is  not  suitable  as  it  is 
strongly  acted  upon),  in  a  Rossler  gas-furnace,  to  the  highest 
possible  temperature.  [Relative  to  the  placing  of  the  crucible, 
see  sodium  nitrite,  page  6.]  As  soon  as  the  mass  begins  to  glow, 
stir  thoroughly  with  an  iron  spatula,  whereupon  the  mass,  which 
at  the  beginning,  in  consequence  of  the  easy  fusibility  of  the 
lead  oxide,  is  in  a  state  of  fusion,  rapidly  becomes  completely 
dry  and  pulverulent.  The  small  opening  in  the  cover  of  the 
furnace  is  not  closed  during  the  operation.  Make  sure,  by  hold- 
ing a  splinter  in  front  of  it,  that  fresh  air  is  continually  coming 
in  contact  with  the  mixture  to  be  oxidized. 


54          INORGANIC  CHEMICAL   PREPARATIONS. 

(b)  In  a  Wet  Way. 

Add  a  solution  of  190  grams  of  lead  acetate  in 
500  c.c.  of  water  to  500  c.c.  of  a  20%  sodium  hydrox- 
ide solution,  and  treat  the  cooled,  milky,  alkaline 
liquid  with  chlorine,  shaking  during  the  operation, 
until  no  more  precipitate  forms.  Decant  with  water 
and  purify  with  nitric  acid  as  above. 

REACTION:  In  the  presence  of  the  oxygen  of  the 
air,  lead  oxide  expels  the  carbon  dioxide  from  the 
calcium  carbonate,  with  the  formation  of  calcium 
plumbate,  which  corresponds  to  the  orthosilicates: 

2CaCO3  +  PbO  +  O  =  Ca2PbO4  +  2CO2. 

The  plumbate,  which  varies  but  slightly  from  the 
color  of  the  original  mixture,  is  .easily  decomposed  by 
nitric  acid: 

Ca2PbO4+4HNO3  =  2Ca(NO3)2+PbO2+2H2O. 

Lead  peroxide  is  formed  from  the  aqueous  solution 
by  the  action  of  chlorine  on  the  sodium  plumbite: 

Pb(ONa)2  +  2C1  =  PbO2  +  2NaCl. 

TEST:  Upon  heating  with  dilute  nitric  acid,  the 
dark-brown  lead  peroxide  should  impart  no  violet 
color  to  the  supernatant  liquid;  this  color  should  be 
formed,  however,  upon  addition  of  a  drop  of  dilute 
manganous  sulphate  solution.*  Suspended  in  dilute 

*  A  manganous  salt  is  oxidized  in  nitric  acid  solution  by  lead 
peroxide  to  permanganic  acid,  and  nitrous  acid  oxidized  to 
nitric  acid: 

PbO2  +  HNO2  +  HNO3  =  Pb(NO3)2  +  H2O. 


INORGANIC  CHEMICAL   PREPARATIONS.  55 

nitric  acid,  it  should,  upon  the  addition  of  sodium 
nitrite,  go  easily  and  completely  into  solution.  To 
determine  the  amount  of  lead  peroxide  present,  weigh 
off  an  average  sample  of  the  paste,  or  of  the  finely 
pulverized  dried  preparation;  treat  with  dilute  nitric 
acid  in  a  flask  having  a  ground-glass  stopper,  and 
gradually  add  normal  sodium  nitrite  (page  7)  in 
slight  excess,  aiding  the  decomposition  by  shaking 
the  closed  flask  frequently  and  vigorously.  After  all 
the  peroxide  has  gone  into  solution,  dilute  with  much 
water  and  titrate  back,  with  potassium  permanganate, 
the  excess  of  nitrite. 


THORIUM   DIOXIDE,  ThO2. 

Literature:    Erdmann,   Lehrbuch   der  anorganischen   Chemie 
(Braunschweig  1898),  page  601. 

It  is  most  convenient  to  use  the  mantles  which  serve 
for  incandescent  lighting  by  means  of  gas,  as  a  ma- 
terial for  the  preparation  of  pure  thorium  dioxide  in 
the  laboratory. 

Grind  to  a  paste  10  grams  of  the  residues  of  such 
mantles  (corresponding  to  about  20  mantles),  with 
concentrated  sulphuric  acid;  calcine  to  a  dry  powder, 
and  add  gradually,  in  a  finely  pulverized  condition, 
to  a  mixture  of  50  c.c.  of  water  and  50  grams  of  ice, 
stirring  very  thoroughly  during  the  addition.  After 
any  cerium  present  has  been  separated  by  means  of 


$  INORGANIC  CHEMICAL   PREPARATIONS. 

sodium  sulphate,  precipitate  the  thorium  from  the 
solution  in  the  form  of  its  hydroxide,  Th(OH)4,  by 
adding  sodium  nitrite.  For  further  purification,  the 
thorium  hydroxide  may  be  dissolved  in  citric  acid,  the 
impurities  (iron,  etc.)  precipitated  by  means  of  am- 
monia and  ammonium  sulphide,  and  the  thorium  di- 
oxide recovered  by  evaporation  and  ignition;  for  in 
the  presence  of  organic  acids,  no  single  reagent  will 
precipitate  it. 

REACTION:  Thorium  dioxide  is  insoluble  in  the 
ordinary  solvents,  but  is  converted  into  a  very  stable 
sulphate  upon  'heating  with  sulphuric  acid,  which  is 
only  soluble  in  ice-water.  Upon  heating  the  aqueous 
solutions  of  the  thorium  salts,  insoluble  modifications 
are  formed.  Thorium  dioxide  forms  no  stable  salt 
with  nitrous  acid. 

TEST:  Ignite  i  gram  of  thorium  dioxide  with  sul- 
phuric acid;  dissolve  the  dry,  finely  pulverized  sul- 
•  phate  in  10  c.c.  of  ice-water,  and  heat  the  filtrate: 
insoluble  thorium  sulphate  separates,  which,  upon 
calcining,  reforms  the  modification  soluble  in  ice- 
water. — Precipitate  the  cold  sulphate  solution  with 
ammonia  and  dissolve,  in  a  small  amount  of  nitric 
acid,  the  thorium  hydroxide  which  separates.  By 
evaporation  at  ordinary  temperatures,  the  salt 
Th(NO3)4  +  6H2O  crystallizes  in  pointed  double 
pyramids. 


INORGANIC  CHEMICAL  PREPARATIONS.  57 

NITROGEN  TETROXIDE,   N2O4. 

Gently  warm  200  grams  of  commercial  white 
arsenic  (arsenious  oxide),  in  pieces  of  the  size  of  a 
pea,  in  a  tubulated  retort  with  200  c.c.  of  nitric  acid 
of  a  specific  gravity  of  1.38,  the  retort  being  fitted 
with  a  bent  tube  (as  in  Figure  4).  Pass  through  an 
empty  wash-bottle  the  reddish  gas  which  is  evolved; 
then  dry  it  by  means  of  a  tube  filled  with  calcium 
nitrate,  and  finally  conduct  it  into  a  wide  sealing-tube 
which  is  placed  in  a  cooling  mixture  of  salt  and  ice. 
A  dark-green  liquid  condenses  in  this  tube.  Pass  dry 
oxygen  into  this  liquid  until  it  is  decolorized;  then 
seal  the  tube. 

REACTION:  Arsenious  oxide,  As4O6,  reduces  the 
nitric  acid,  being  itself  converted  into  arsenic  acid.* 
In  drying  the  gases,  calcium  chloride  should  not  be 
used;  for  they  would  immediately  contain  chlorine. 
Neither  should  sulphuric  acid  be  used,  as  it  dissolves 
the  gases.  The  condensed  mixture  of  nitrogen  .tri- 
oxide  and  tetroxide  is  converted  into  pure  tetroxide 
by  oxygen. 

TEST:  The  liquid  (nitrogen  tetroxide)  should  have 
a  specific  gravity  of  1.45  and  boil  at  25-26°.  By  cool- 
ing strongly,  it  should  solidify,  forming  colorless, 
prismatic  crystals  which  melt  at  —9°. 

*  For  the  utilization  of  the  arsenic  acid  residues,  see  page  68. 


58          INORGANIC  CHEMICAL  PREPARATIONS. 


INORGANIC  CHEMICAL   PREPARATIONS.          59 

PURE  ANHYDROUS   NITRIC  ACID,   HNO3. 

In  a  retort  having  a  bent  tube  and  an  attached 
condenser  (see  .illustration),  distil  on  the  gas-stove 
\  liter  of  commercial  nitric  acid  with  \  liter  of  con- 
centrated sulphuric  acid.  Collect  by  itself  the  dis- 
tillate which  first  comes  over,  until  a  sample  caught 
in  a  test-tube  no  longer  gives  a  precipitate  with  silver 
nitrate.  At  a  gentle  heat  and  in  not  too  light  a  place, 
redistil,  through  the  bent  tube,  the  main  portion 
mixed  with  an  equal  volume  of  pure  concentrated 
sulphuric  acid,  testing  the  first  portion  of  the  dis- 
tillate again  for  chlorine.  Collect  the  anhydrous  acid 
in  a  flask  which  is  closed  with  glass  wool.  After  the 
distillation  is  finished,  place  the  flask,  which  is  fitted 
with  a  double-bored  rubber  stopper,  in  a  water-bath 
which  is  at  40°,  and  aspirate  air  through  the  acid  by 
means  of  a  water  vacuum  pump.  The  air  must  pre- 
viously be  dried  by  sulphuric  acid  and  filtered  through 
a  tube  filled  with  cotton.  Keep  the  acid  in  a  dark 
place. 

REACTION:  The  water  which  is  mixed  with  the 
nitric  acid  (an  acid  which  begins  to  boil  at  86°)  is 
held  back  by  careful  distillation  with  sulphuric  acid. 
Chlorine  distils  with  the  first  portions.  If  no  bent 
tube  is  used,  sulphuric  acid  is  constantly  carried  over 
mechanically  into  the  distillate;  also,  by  too  rapid 
distillation,  sulphuric  acid  vapors  are  carried  over. 
Bright  sunlight  decomposes  nitric  acid.  The  oxides 


60          INORGANIC  CHEMICAL  PREPARATIONS. 

of  nitrogen  can  be  removed  from  the  acid  by  dry  air. 
Absolutely  pure  and  colorless  nitric  acid  can  be  ob- 
tained by  distillation  under  diminished  pressure;  * 
this  operation,  however,  cannot  be  recommended  for 
the  purpose  of  practice;  for  it  cannot  be  carried  out 
safely  except  with  special  care  in  the  method  of  pro- 
cedure. 

TEST:  The  acid  should  not  show  the  slightest  tur- 
bidity with  silver  nitrate.  A  few  cubic  centimeters 
evaporated  on  the  water-bath,  in  a  small  platinum 
dish,  should  leave  no  weighable  residue;  and,  upon 
washing  out  the  dish  with  water,  the  liquid  should 
not  become  turbid  with  barium  chloride.  (Direct 
treating  of  the  nitric  acid  with  barium  nitrate,  shows 
the  presence  of  only  larger  amounts  of  sulphuric 
acid).  The  acid  should  be  colorless  and  have  a  specific 
gravity  of  1.54. 


PURE  AMMONIUM  CHLORIDE,  NH4C1. 

Literature:    Kriiss,  Annalen  238,  51. 

Dissolve  i  kilogram  of  commercial  sal  ammoniac 
in  i \  liters  of  boiling  water,  filter  through  a  hot-water 
filter,  and  heat  with  100  c.c.  of  concentrated  nitric 
acid  until  no  more  acid  vapors  are  evolved.  Filter  off 
the  ammonium  chloride  which  separates  upon  cool- 

*  Erdmann,    Lehrbuch    der    anorganischen    Chemie    (Braun- 
schweig 1898),  page  175. 


INORGANIC  CHEMICAL   PREPARATIONS.          6 1 

ing  by  means  of  a  pump  and  recrystallize  from  hot 
water. 

REACTION:  The  organic  bases  usually  present  in 
large  amounts  in  commercial  sal  ammoniac  (from  gas- 
liquor)  are  destroyed  by  heating  with  nitric  acid. 

TEST:  The  salt  should  be  bright  white  and  dissolve 
clear  in  water,  forming  a  transparent  liquid.  5  grams 
volatilized  in  a  weighed  platinum  dish  at  a  gentle 
heat  on  the  gas-stove,  should  leave  no  carbonaceous 
residue,  and  should  always  leave  no  weighable 
residue. 


AMMONIUM   BICARBONATE,  (NH4)HCO3. 

Place  concentrated  aqua  ammonia  in  a  small  flask 
which  is  closed  by  a  stopper  bearing  a  short  glass 
tube.  Through  this  glass  tube,  which  should  extend 
nearly  to  the  surface  of  the  liquid  but  not  dip  into  it, 
conduct  carbon  dioxide,  generated  in  a  Kipp  appa- 
ratus. The  neutral  ammonium  carbonate,  which  pre- 
cipitates at  first,  redissolves,  and,  after  the  liquid  has 
stood  for  some  time  under  the  pressure  of  the  carbon 
dioxide,  the  acid  salt  separates.  More  dicarbonate  is 
obtained  from  the  mother-liquor  by  covering  it  with 
a  layer  of  alcohol.  Preserve  the  salt  in  glass  tubes 
which  have  been  filled  with  carbon  dioxide  and  then 
sealed. 

TEST:   Ammonium  dicarbonate  forms  hard,  bright 


62          INORGANIC  CHEMICAL   PREPARATIONS. 

rhombic  prisms,  which  are  very  volatile.  An  aqueous 
solution  should  not  become  turbid  upon  the  addition 
of  calcium  chloride. 


HYDROCYANIC    ACID,    HCN. 

(P rustic  Acid.) 

Literature:     Erdmann,   Lehrbuch  der  anorganischen   Chemie 
(^Braunschweig  1898),  page  463. 

Distil  on  the  gas-stove,  in  a  well-ventilated  place, 
500  grams  of  coarsely  pulverized  yellow  prussiate  of 
potash,  with  350  grams  of  concentrated  sulphuric  acid 
and  700  c.c.  of  water,  in  a  retort  'having  an  ascending 
tube  and  a  descending  condenser  (see  illustration, 
page  58).  Attach  two  Woulff  bottles  air-tight  to  the 
condenser,  and  surround  the  bottles  with  ice;  conduct 
the  vapors  evolved  from  the  last  bottle  into  cold 
water.  The  insoluble  residue  formed  in  the  retort  * 
causes  a  little  bumping;  but,  by  an  even,  careful  heat- 
ing, the  breaking  of  the  retort  need  not  be  feared. 
The  distillate  is  almost  completely  pure.  If  there  is 
need  for  absolutely  anhydrous  hydrocyanic  acid,  fill 
the  first  Woulff  bottle,  previous  to  the  distillation, 
half  full  of  porous  calcium  chloride  (page  24)  and, 
at  the  end  of  the  operation,  place  it  in  warm  water, 
in  order  to  distil  its  contents  into  the  second  bottle. — 

*  For   the   utilization    of   these    residues,    see   prussian   blue, 
page  112, 


INORGANIC   CHEMICAL   PREPARATIONS.          63 

The  product  should  not  be  kept  in  an  anhydrous  con- 
dition, but  in  dilute  solution;  and  the  aqueous  hydro- 
cyanic acid  keeps  still  better  upon  the  addition  of  a 
drop  of  dilute  mineral  acid  to  each  100  c.c.  of  the  so- 
lution. 

TEST:  Anhydrous  prussic  acid  is  an  extremely 
volatile,  mobile,  colorless  liquid,  which,  when  put 
upon  the  skin,  produces  a  feeling  of  cold,  like  evapo- 
rating ether.  It  boils  at  27°  and  solidifies  to  a  crys- 
talline mass  in  a  cooling  mixture.  The  aqueous  solu- 
tion does  not  redden  litmus  paper. 


UREA,  CON2H4. 

(i)  Dissolve  the  crude  potassium  cyanate  (which 
is  prepared  according  to  the  method  on  page  10)  from 
the  frit,  which  contains  chromic  acid,  by  grinding  in 
a  mortar  with  cold  water.*  To  the  clear  aqueous 
solution,  add  a  concentrated  solution  of  150  grams  of 
ammonium  sulphate  and  evaporate  to  dryness  on  the 
water-bath,  stirring  during  the  evaporation.  Extract 
the  residue  with  alcohol,  which  upon  evaporation 
yields  urea.  Crystallize  the  urea  from  amyl  alcohol;  f 
take  up  the  residue  from  the  evaporated  mother-liquor 
in  water,  neutralize  with  nitric  acid,  and  separate  from 

*  Hot  water  decomposes  the  potassium  cyanate  (compare  with 
page  12). 
1 700-800  grams  of  amyl  alcohol  are  necessary. 


64         INORGANIC  CHEMICAL  PREPARATIONS. 

it  the  more  difficultly  soluble  and  easily  crystallizable 
urea  nitrate. 

(2)  After  filtering  off  the  cyanate  which  crystallizes 
out,  immediately  add  the  alcoholic  mother-liquor 
(which  contains  potassium  cyanate,  mentioned  on 
page  12)  to  a  solution  of  70  grams  of  ammonium  sul- 
phate in  loo  c.c.  of  'hot  water,  shaking  during  the 
addition.  Distil  off  the  alcohol,  evaporate  the  residue 
to  dryness  with  the  addition  of  some  barium  car- 
bonate, and  extract  with  96%  alcohol,  a  considerable 
amount  of  the  urea  going  into  solution.  By  recrys- 
tallizing  once  from  amyl  alcohol,  -the  carbamid  is  ob- 
tained quite  pure. 

REACTION: 

2KCNO  +  (NH4)2SO4  =  2NH4CNO  +  K2SO4; 
NH4CNO  =  NH2.CO.NH2. 

TEST:  Urea  should  form  colorless,  four-sided 
prisms  or  plates,  having  a  melting-point  of  132°,  and 
should  dissolve  clear  in  an  equal  weight  of  cold  water. 
The  solution  should  give  a  crystalline  precipitate  with 
oxalic  acid. 


PHOSPHORIC  ACID,  H3PO4. 

Heat  127  grams  of  white  phosphorus  and  1400  c.c. 
of  nitric  acid  (specific  gravity  1.20)  in  a  retort,  having 
a  receiver  attached.  The  phosphorus 'melts  and  the 
reaction  takes  place  quietly.  From  time  to  time, 


INORGANIC  CHEMICAL   PREPARATIONS.          6$ 

the  distillate  must  be  poured  back.  When  the  phos- 
phorus has  gone  completely  into  solution  (after  10-12 
hours),  evaporate  in  a  platinum  dish,  until  a  sample 
taken  out  with  a  glass  rod  no  longer  gives  a  test  for 
nitric  acid  with  concentrated  sulphuric  acid  and  fer- 
rous sulphate  solution.  The  temperature  should  not 
exceed  188°.  The  acid,  treated  with  mercuric  chloride 
solution,  should  show  the  absence  'of  phosphorous 
acid.  Then  treat  it,  w'hile  warm,  with  hydrogen  sul- 
phide, until,  even  upon  standing,  no  more  sulphide  of 
arsenic  precipitates.  Dilute  with  water,  filter,  and 
again  slowly  evaporate  until  a  thermometer  dipped 
into  it  shows  a  temperature  of  160°. 

TEST:    The  acid  should  show  a  specific  gravity  of 
1.88  and  be  free  from  arsenic  and  phosphorous  acid. 


PHOSPHORUS   TRISULPHIDE,    P2S3. 

Mix  310  grams  of  red  phosphorus  with  480  grams 
of  pulverized  sulphur,  and  add,  little  by  little,  by 
means  of  a  spoon,  to  a  Hessian  crucible  which  is 
heated  with  a  Bunsen  burner.  After  the  addition  of 
each  portion,  close  the  crucible  with  a  cover,  where- 
upon the  reaction  must  immediately  take  place.  After 
the  whole  of  the  mixture  has  been  added,  let  the  cruci- 
ble cool  to  such  an  extent  that  the  mass  is  just  molten; 
then  pour  the  sulphide  of  phosphorus  upon  an  iron 


66          INORGANIC  CHEMICAL   PREPARATIONS. 

plate.  Break  into  pieces  the  solidified  product,  while 
it  is  still  warm,  and  put  it  into  a  well-stoppered  bottle. 
Phophorus  trisulphide  forms  a  hard,  gray,  easily 
pulverizable  mass,  which,  upon  standing  in  the  air,  be- 
comes moist  and  slimy,  hydrogen  sulphide  being 
evolved. 


CALCIUM   PHOSPHIDE,   CaP. 

Literature:  Erdmann,  Lehrbuch  der  anorganischen  Chemie 
(Braunschweig  1898),  page  551. 

Cut  a  round  cover  from  strong  sheet  iron  2  mm. 
thick,  to  fit  a  crucible  which  is  about  6^  cm.  wide  and 
12  cm.  high,  and  which  is  made  of  dense,  difficultly 
fusible  clay.  In  the  center  of  the  cover  Have  a  circular 
opening  2.5  cm.  in  diameter,  through  which  passes 
an  iron  tube  30  cm.  in  length.  To  the  upper  end  of 
this  iron  tube,  join  a  slightly  smaller,  thin-walled  glass 
tube  of  15  cm.  in  length.*  After  the  iron  tube  has 
been  placed  upright  in  the  crucible,  fill  the  latter  with 
100  grams  of  lime  (made  from  marble)  in  pieces  the 
size  of  a  hazelnut,  put  on  the  cover,  and  heat  in  the 

*  In  order  to  accomplish  this,  wind  some  thin  asbestos  thread 
around  the  glass  tube  and  twist  it  into  the  iron  tube,  having 
previously  moistened  the  asbestos  with  water-glass.  Cover  the 
joints  with  a  pasty  mixture  of  powdered  pyrolusite  and  water- 
glass,  and  dry  at  a  gentle  heat.  The  glass  tube  must  be  suffi- 
ciently wide  to  permit  an  easy  passage  of  the  pieces  of  stick 
phosphorus. 


INORGANIC  CHEMICAL   PREPARATIONS.          6? 

Rossler  furnace  (page  117).  After  the  crucible  has  be- 
come red-hot,  add,  through  the  glass  tube,  65  grams 
of  stick-phosphorus  in  carefully  dried  pieces  of  5-10 
grams  each.  Immediately  after  the  addition  of  each 
piece  of  phosphorus,  close  the  glass  tube  with  a  cork. 


FIGURE  5. — Preparation  of  Calcium  Phosphide. 

The  action  of  the  phosphorus  on  the  lime  is  made 
known  each  time  by  the  evolution  of  phosphorus 
pentoxide  in  the  form  of  white  clouds  from  the  chim- 
ney of  the  furnace.  If  the  reaction  fails  to  take  place, 
lift  up  the  iron  tube  a  little,  in  order  to  aid  the  en- 
trance of  the  phosphorus  into  the  crucible.  While  at 
the  beginning  but  a  minimum  of  the  phosphorus  does 
not  enter  the  reaction,  the  end  of  the  operation  is 
shown  by  the  appearance  of  many  fumes.  Then  ex- 


68          INORGANIC  CHEMICAL   PREPARATIONS. 

tinguish  the  flame,  lift  the  crucible  out,  and,  as  soon 
as  the  product  has  cooled  down  until  it  is  but  slightly 
warm,  put  it  into  a  well-stoppered  preparation  bottle. 
Yield:  140  grams. 

REACTION:  ;CaO  +  7?  =  Ca2P2O7  +  sCaP. 

TEST:  Calcium  phosphide  forms  dark,  hard,  irides- 
cent pieces,  which,  upon  throwing  into  water,  evolve 
spontaneously  inflammable  phosphoretted  hydrogen: 

2CaP  +  4H2O  =  2Ca(OH)2  +  P2H4. 


ARSENIC   ACID,    2H3AsO4  +  H2O. 

Pour,  from  the  unchanged  pieces  of  white  arsenic, 
the  mother-liquor  obtained  in  the  preparation  of  ni- 
trogen tetroxide  (page  57),  evaporate  to  dryness  in 
a  porcelain  dish,  and  redissolve  the  residue,  by  con- 
tinued heating,  in  a  small  amount  of  water.  The  so- 
lution must  be  free  from  arsenious  acid;  otherwise, 
it  is  again  evaporated  to  dryness  after  the  addition 
of  nitric  acid,  and  again  redissolved.  When  the  solu- 
tion is  pure,  evaporate  it  to  a  syrup  and  let  it  crystal- 
lize in  a  closed  flask  at  winter  temperature,  if  neces- 
sary, with  the  addition  of  a  small  crystal  of  arsenic 
acid.  In  case  just  the  right  concentration  is  obtained, 
very  beautiful  large  compact  shining  crystals  form, 
which  have  the  composition  H8AsO9;  and  this  com- 
pound probably  corresponds  to  the  constitution 
(HO)4As— O— As(OH)4.  If  crystallization  results 


INORGANIC  CHEMICAL   PREPARATIONS.          69 

too  rapidly,  filter  off  the  mass;  melt  the  crystals  at  a 
gentle  heat  in  a  flask  having  an  air-tight  stopper,  or 
in  a  sealed  tube,  and  allow  the  fused  mass  to  crystal- 
lize slowly,  obtaining  larger  crystals. 

REACTION:    The  arsenious  oxide  is  oxidized  ac- 
cording to  the  equation: 


As4O6  +  4HN03  +  4H2O  =  4H3AsO4  +  2N2O 


Upon  evaporating  to  dryness,  as  is  necessary  in  order 
to  get  rid  of  the  excess  of  the  nitric  acid,  compounds 
are  formed  containing  less  water,  which  upon  long 
treatment  with  a  small  amount  of  water  go  over  into 
normal  arsenic  acid. 

TEST:  The  acid  should  form  transparent  rhombic 
prisms  or  plates  of  the  composition  2H3AsO4  +  H2O, 
which  are  very  deliquescent  and  dissolve  in  water,  with 
a  considerable  lowering  of  the  temperature.  It  melts 
at  100°,  losing  its  crystal  water  and  forming  normal 
arsenic  acid,  AsO4H3,  which  is  also  very  easily  solu- 
ble and  crystallizes  in  small  needles.  The  solution 
reacts  and  tastes  strongly  acid,  and,  after  adding  an 
excess  of  ammonia,  gives  with  magnesia  mixture  a 
crystalline  precipitate  of  magnesium  ammonium  ar-« 
senate,  NH4MgAsO4,  which  upon  being  treated  with 
silver  nitrate  solution  changes  into  reddish-brown 
silver  arsenate,  Ag3AsO4. 

The  solution  of  arsenic  acid  should  give  no  test  for 
nitric  acid  with  ferrous  sulphate.  A  highly  diluted- 
solution  treated  with  a  drop  of  hydrochloric  acid 


7O          INORGANIC  CHEMICAL   PREPARATIONS. 

should,  upon  adding  an  equal  volume  of  hydrogen 
sulphide  solution,  remain  at  first  clear,  and  should 
become  turbid  only  after  long  standing.  A  solution 
of  the  acid  in  fuming  hydrochloric  acid  should  give 
immediately,  with  hydrogen  sulphide  gas,  a  thick  yel- 
low precipitate  of  arsenic  pentasulphide,  As2S5,  which 
must  be  filtered  off  and  washed  without  warming. 
Hydrogen  sulphide  does  not  act  on  a  cold,  weak  acid 
solution  of  arsenic  acid,  but,  under  such  conditions, 
pure  arsenic  pentasulphide,  As2S5,  precipitates  from  a 
warm  solution.  Arsenic  pentasulphide  is  of  great  im- 
portance in  the  analytical  separation  and  determina- 
tion of  arsenic.  It  is  the  most  convenient  form  in 
which  arsenic  can  be  obtained  for  weighing.*  [Con- 
cerning the  treatment  of  arsenic  compounds  for  the 
presence  of  antimony,  and  the  separation  of  arsenic 
from  antimony,  see  Erdmann,  Lehrbuch  der  anorgan- 
ischen  Chemie,  pages  394  and  403.] 

*  These  conditions  have  been  already  established  by  Robert 
Bunsen,  but  the  directions  of  Bunsen  have  recently  been  as- 
sailed in  an  unjustifiable  manner.  Piloty  and  Stock  first  showed, 
in  1897,  that  Bunsen's  method  for  precipitating  arsenic  as  penta- 
sulphide is,  in  fact,  an  excellent  one,  if  the  precipitation  is 
carried  out  exactly  according  to  Bunsen's  directions,  in  a  warm, 
very  weak  hydrochloric  acid  solution;  for  warm  concentrated 
hydrochloric  acid  partially  reduces  the  arsenic  acid,  and  even 
changes  the  sulphide  already  precipitated. 


INORGANIC  CHEMICAL    PREPARATIONS.          7 1 

CRYSTALLINE  ARSENIOUS   OXIDE,   As4O6. 

(Flowers  of  Arsenic,  White  Arsenic.} 

Literature:  Friedheim  and  Michaelis,  Berichte  d.  d.  chem. 
Ges.  28,  I4I7>  note;  Erdmann,  Lehrbuch  der  anorganischen 
Chemie,  page  385. 

(1)  With  a  freshly  prepared  saturated  aqueous  so- 
lution of  sulphurous  acid  (page  16),  dilute  to  i  liter 
75  grams  of  the  syrup  which  remains  after  the  prep- 
aration of  crystalline  arsenic  acid  (page  68),  and  let  it 
stand  in  a  well-stoppered  flask.    During  the  course  of 
a  few  weeks  arsenious  oxide  separates  in  beautiful 
shining  octahedra.    Pour  off  the  liquid,  and  wash  the 
crystals  with  a  little  water,  alcohol,  and  ether. 

REACTION: 

4H3AsO4  +  4H2SO3  =  As4O6  +  4H2SO4  +  6H2O. 

(2)  Dissolve  commercial  arsenious  acid  to  a  syrup 
in  50%  caustic  potash  solution,  and  dilute  with  twenty 
times  its  volume  of  water.     At  first,  crusts  which  are 
indistinctly  crystalline  separate;    but  if  the  solution 
is  poured  off  from  these,  larger  individual  octahedra 
are  obtained. 

REACTION:  The  salts  of  arsenious  acid  are  stable 
only  in  the  presence  of  an  excess  of  alkali,  or  in  con- 
centrated solution;  but  when  much  water  is  present, 
they  decompose,  with  the  formation  of  arsenious 
oxide. 

(3)  Treat  40  grams  of  commercial  arsenious  acid,  in 


72         INORGANIC  CHEMICAL  PREPARATIONS. 

a  250  c.c.  distilling-flask,  with  100  c.c.  of  methyl  alco- 
hol; then  pass  in  hydrochloric  acid,  cooling-  down  the 
liquid  as  it  warms  up,  in  order  to  avoid  a  premature 
loss  of  the  alcohol.  After  saturation,  distil  on  the 
water-bath  into  a  well-closed  receiver,  stopping  the 
distillation  when  5  c.c.  of  liquid  still  remains  in  the 
flask;  then  dilute  the  distillate  with  water,  until  crys- 
tals just  begin  to  separate.  Filter  off  the  crystalline 
arsenious  oxide,  wash  with  water,  and  dry  at  110°. 

REACTION:  The  arsenic  is  converted  into  the  quite 
volatile  methyl  ester  of  arsenious  acid,  while  the  main 
portion  of  the  antimony,  which  is  there  >as  an  im- 
purity, remains  behind.  The  ester  is  decomposed  by 
water;  and  arsenious  oxide  separates,  while  any  an- 
timony that  has  passed  over  remains  in  solution  in 
the  very  strongly  acid  liquid. 

TEST:  Heat  a  small  crystal  in  a  dry  test-tube  or 
on  a  piece  of  platinum  foil:  it  should  volatilize,  leav- 
ing no  residue  (though  with  the  octahedra  prepared 
according  to  the  second  method  this  is  not  always 
the  case,  because  they  frequently  contain  some  al- 
kali).— Weigh  0.4912  gram  of  the  pulverized  arse- 
nious oxide  into  a  large  beaker,  add  100  c.c.  of  water 
and  i  gram  of  sodium  dicarbonate,  and  titrate  with 
normal  iodine  solution.  10  c.c.  of  the  normal  solution 
should  be  required. 


INORGANIC  CHEMICAL  PREPARATIONS.         73 

ANTIMONIOUS  CHLORIDE,  SbCl3. 

In  a  flask  under  a  hood,  heat  100  grams  of  pow- 
dered stibnite  with  500  c.c.  of  commercial  hydro- 
chloric acid,  adding  gradually  about  4  grams  of 
potassium  chlorate.  When  the  ore  has  disappeared, 
filter  off  the  sulphur  through  glass  wool,  «and  distil 
in  a  retort.  At  first  aqueous  hydrochloric  acid  comes 
over,  then  a  concentrated  antimony  trichloride  solu- 
tion colored  yellow  by  ferric  chloride,  and  finally  pure 
antimony  trichloride,  wThic'h  solidifies  to  a  beautiful 
white  crystalline  mass.  Each  of  these  products  is 
collected  separately.  The  pure  antimony  trichloride 
is  sealed  in  a  preparation-tube  or  a  small  flask;  and 
the  antimony  trichloride  solution  is  decomposed  with 
much  cold  water,  thus  precipitating  antimony  oxy- 
chloride  as  a  fine  white  powder. 

REACTION:  The  reaction,  which  at  first  is  energetic, 
becomes  slower,  but  is  hastened  by  the  addition  of  the 
oxidizing  agent. 

Sb2S3  +  6HC1  =  2Sb€l3 


TEST:  Antimony  trichloride  should  melt  at  73°, 
boil  at  223°,  and  crystallize  from  carbon  disulphide  in 
bright  rhombic  crystals. 


74         INORGANIC  CHEMICAL  PREPARATIONS. 

BASIC  CHLORIDE  OF  ANTIMONY,  Sb4O5Cl2. 

(Powder  of  Algaroth.} 

Literature:  G.  E.  Stahl,  Zufallige  Gedanken  und  niitzliche 
Bedenken  iiber  den  Streit  von  dem  sogenannten  Sulfure,  Halle 
1715,  page  346. 

Intimately  mix  60  grams  of  pulverized  sulphide  of 
antimony  and  140  grams  of  mercuric  chloride  by 
means  of  a  mortar,  and  distil  slowly  from  a  glass  re- 
tort on  the  gas-stove,  using  a  small  flame.  For  a 
receiver,  use  a  flask,  the  neck  of  which  has  been 
broken  off,  and  heat  the  neck  of  the  retort  from  time 
to  time  with  a  Bunsen  burner,  in  order  to  melt  the 
antimony  trichloride  which  has  solidified  in  it.  Dis- 
solve the  distillate  in  a  small  amount  of  warm  hy- 
drochloric acid,  and  pour  it  into  a  large  amount  of  hot 
water.  Wash  the  precipitate  which  forms,  by  decan- 
tation,  and  dry  it. 

REACTION: 

Sb2S3  +  3HgCl2  =  2SbCl3  +  3HgS; 
4SbCl3  +  sH2O  =  Sb4O5Cl2  +  loHCl. 

TEST:  The  white,  crystalline  powder  should  be  in- 
soluble in  water,  alcohol,  and  ether,  but  soluble  in 
carbon  disulphide  and  in  chloroform.  Upon  heating, 
it  should  give  a  sublimate  of  antimonious  chloride  and 
leave  a  residue  of  oxide  of  antimony. 


INORGANIC  CHEMICAL  PREPARATIONS.          ?$ 

SULPHATE   OF  ANTIMONY,   Sb2(SO4)3. 

Add  20  grams  of  finely  pulverized  antimony  to  400 
grams  of  pure  boiling  sulphuric  acid,  and  heat  in  a 
platinum  dish  until  the  metal  has  disappeared.  A  por- 
tion of  the  sulphate  crystallizes  in  small  white  needles^ 
while  the  acid  is  still  hot;  the  remainder  crystallizes 
upon  cooling.  Filter  on  a  platinum  cone,  and  dry 
the  preparation  on  a  porous  plate. 


BISMUTH   NITRATE,   Bi(NO3)3  +  sH2O; 

BASIC   BISMUTH   NITRATE, 
BiO.NO3  +  BiO.OH; 

BISMUTH   HYDROXIDE,   BiO.OH. 

Heat  to  a  low  red  heat  100  grams  of  commercial 
bismuth  with  50  grams  of  sodium  nitrate,  using  a 
nickel  dish.  After  the  metal  is  completely  oxidized, 
heat  with  250  c.c.  of  water,  with  the  addition  of  a 
solution  of  20  grams  of  sodium  hydroxide  in  150  c.c. 
of  water.  After  filtering  off  the  bismuth  oxide  on  a 
platinum  cone,  dissolve  the  oxide  in  a  hot  mixture  of 
140  c.c.  of  concentrated  nitric  acid  and  200  c.c.  of 
water;  filter  through  asbestos,  and  evaporate  to  crys- 
tallization.— Evaporate  the  mother-liquor  consider- 
ably and  pour  it  into  ^  liter  of  boiling  water,  the  basic 
bismuth  nitrate  separating  as  a  heavy  white  powder. 


76         INORGANIC  CHEMICAL   PREPARATIONS. 

After  decanting,  collect  this  on  a  filter  and  dry  with- 
out warming. — Or,  precipitate  the  acid  liquor  with 
ammonia,  wash  the  bismuth  oxyhydrate  by  decan- 
tation,  and  preserve  as  a  paste. 

REACTION:  Bismuth,  such  as  is  used  in  the  arts,  has 
usually  arsenic  and  antimony  as  impurities,  the  oxides 
of  which  dissolve  in  sodium  hydroxide  upon  heating. 

TEST:  The  amount  of  bismuth  in  the  crystallized 
nitrate  is  determined  in  a  weighed  sample,  by  convert- 
ing it  into  the  oxide  by  first  carefully  'heating  in  a 
covered  porcelain  crucible,  then  heating  strongly  and 
weighing  the  product.  Also  dissolve  a  sample  in 
water  acidified  with  nitric  acid,  add  this  solution  to 
an  excess  of  hot  sodium  hydroxide,  and  test  the  fil- 
trate for  arsenic  and  antimony. 


BISMUTH   IODIDE,   BiI3. 

Grind  20  grams  of  iodine  with  35  grams  of  finely 
pulverized  bismuth  in  a  mortar,  introduce  rapidly  into 
a  retort,  and  heat  slowly  on  the  gas-stove.  After 
union  has  taken  place,  drive  off  the  small  excess  of 
iodine  by  means  of  a  current  of  carbon  dioxide;  then 
raise  the  temperature  until  the  bismuth  iodide  sub- 
limes in  very  large  crystals,  which  resemble  iodine. 

TEST:  Boiling  water  should  convert  the  powdered 
preparation  into  the  red  oxyiodide. 


INORGANIC  CHEMICAL   PREPARATIONS,          // 

BISMUTH   OXYIODIDE,   BiOI. 

Literature:    B.   Fischer,   Die  neueren  Arzneimittel,  III.  Aufl. 
page  20. 

Dissolve  95.4  grams  of  the  pulverized  crystalline 
bismuth  nitrate  (page  75)  by  gently  heating  with 
120-160  c.c.  of  glacial  acetic  acid;  also  dissolve  33.2 
grams  of  potassium  iodide  and  50  grams  of  crystal- 
lized sodium  acetate  in  2  liters  of  cold  water.  '  Place 
the  second  solution  in  a  dish  and  let  the  first  flow 
into  it  in  a  very  small  stream  from  a  drop-funnel,  stir- 
ring constantly  during  the  addition.  At  the  place 
where  the  liquids  meet,  a  greenish-black  precipitate 
forms  at  first,  which,  upon  stirring,  changes  to  a 
lemon-yellow  color.  Upon  further  addition  of  the 
bismuth  nitrate  solution,  the  product  changes  to  a 
brick-red  color.  The  precipitate  settles  very  well. 
Decant,  filter,  and  dry  at  100°.  Yield:  78  grams. 

REACTION:  Bi(NO3)3  +  3KI  ==  BiI3  +  3KNO3; 
Bil  3  +  H2O  =  BiOI  +  2HI. 

The  hydriodic  acid  is  decomposed  by  the  sodium 
acetate,  and  the  alkaline  iodide  thus  formed  again  en- 
ters the  reaction. 

TEST:  Heated  in  a  dry  test-tube,  the  preparation 
should  give  off  violet  iodine  vapors,  and  leave  a 
residue  of  bismuth  oxide.  Upon  shaking  with  water, 
it  should  produce  no  'haloid  acid,  and  should  be  free 
from  arsenic  (test  according  to  directions  on  page  27, 


?  INORGANIC  CHEMICAL   PREPARATIONS. 

with  the  addition  of  zinc)  and  subnitrate  of  bismuth. 
— 0.2  gram  shaken  with  2  grams  of  dilute  sulphuric 
acid  should  give  a  filtrate  which,  when  mixed  with 
twice  its  volume  of  concentrated  sulphuric  acid, 
should  produce,  upon  adding  a  drop  of  indigo  solu- 
tion, a  permanent  blue  color  (decolorization  indicates 
nitric  acid). 


HYDROGEN   PEROXIDE,   H2O2. 

Literature:     Erdmann,    Lehrbuch   der  anorganischen   Chemie 
(Braunschweig  1898),  page  154. 

(1)  Mix  20  c.c.  of  concentrated  sulphuric  acid  with 
200  c.c.  of  water  in  a  beaker,  carefully  cool  the  liquid 
in  a  cooling  mixture  of  ice  and  salt,  and  add,  while 
stirring,  moist  hydrated  barium  peroxide,  until  the 
solution  has  but  a  slight  acid  reaction.     Let  the  solu- 
tion settle,  filter,  and  add  to  the  liquid,  which  is  still 
ice-cold,  dilute  barium  hydroxide,  until  a  test  by  the 
capillary  method  *  shows  the  presence  of  neither  sul- 
phuric acid  nor  barium  in  the  solution.     Filter  the 
turbid  liquid  and  distil  in  vacuo,  at  about  20  mm. 
pressure. 

(2)  It  is  more  convenient  to  start  with  a  3%  solu- 
tion of  commercial  hydrogen  peroxide.       For  this 
purpose,  do  not  take  less  than  J  liter  of  hydrogen 
peroxide  solution;    place  it  in  a  thick-walled,  round 

*  See  note,  page  2. 


INORGANIC  CHEMICAL   PREPARATIONS.          7$ 

bottomed  i-liter  flask  having  a  long  neck,  and  evapo- 
rate to  about  100  c.c.  on  the  water-bath,  at  75°,  the 
flask  being  connected  with  a  filter-pump.  Distil  the 
residue  from  a  fractioning-flask,  in  the  most  complete 
vacuum  obtainable,*  catching  the  distillate  in  a  re- 
ceiver cooled  by  ice.  At  first,  aqueous  hydrogen 
peroxide  distils;  finally,  the  pure  product,  the  im- 
purities remaining  behind, 
REACTION:  The  reaction, 

Ba(OH)4  +  H2S04  =  BaSO4  +  H2O2  +  2H2O, 

takes  place  only  in  a  cold  solution,  and  at  not  too 
great  a  concentration.  If  these  conditions  are  not 
adhered  to,  much  oxygen  is  'evolved,  and  the  yield  is 
reduced  to  a  minimum. 

TEST:  Anhydrous  hydrogen  peroxide  should  form  a 
thick  syrup,  which  immediately  blisters  the  skin  white; 
it  should  decompose  easily,  should  have  a  specific 
gravity  of  1.46  and  a  boiling-point  of  69°  at  20  mm. 
pressure.  The  aqueous  solution  should  have  a  pe- 
culiar characteristic  taste,  and  should  give  with  dilute 
sulphuric  acid,  ether,  and  a  drop  of  dilute  potassium 
dichromate  solution,  an  intensely  blue-colored  com- 
pound, soluble  in  ether.  It  s'hould  be  free  from  hydro- 
chloric acid,  sulphuric  acid,  and  barium.  For  pre- 
serving, it  is  made  more  stable  by  the  addition  of  i% 
alcohol.  To  determine  the  amount  of  hydrogen 

*  To  render  a  cork  stopper  air-tight  in  a  vacuum  distillation, 
use  thick  collodion,  laid  on  by  means  of  a  brush  or  a  feather. 


8O          INORGANIC  CHEMICAL   PREPARATIONS. 

peroxide  present,  decompose  i  c.c.  of  the  solution, 
in  a  nitrometer,  with  an  excess  of  permanganate  and 
dilute  sulphuric  acid;  or,  titrate  5  c.c.,  in  sulphuric 
acid  solution,  with  tenth  normal  permanganate. 


DISULPHUR   BICHLORIDE,   S2C12; 
SULPHUR  BICHLORIDE,   SC12. 

Melt  300  grams  of  sulphur  in  a  tubulated  retort  on 
the  gas-stove,  using  a  small  flame,  and  conduct 
through  a  glass  tube  a  very  rapid  current  of  dry. 
chlorine  close  to  -the  surface  of  the  melted  sulphur. 
Rectify,  from  a  flask,  the  chloride  (which  -distils 
rapidly),  using  a  fractioning-column;  and  there  is 
left  a  residue  of  the  sulphur  which  was  dissolved. 

Cool  67.5  grams  of  the  disulpliur  dichlorrde  thus 
obtained,  to  o°,  and  saturate  it  with  dry  chlorine.  The 
sulphur  dichloride  obtained  in  -this  manner  must 
weigh  103  grams.  Preserve  this  product  in  a  bottle 
that  is  well-stoppered  and  -wired. 

REACTION:  Upon  rectifying  the  chloride  of  sul- 
phur, the  higher  chlorides  change  to  disulphur  di- 
chloride; on  the  other  hand,  at  o°,  disulphur  dichlo- 
ride unites  with  another  molecule  of  chlorine: 


TEST:    Disulphur  dichloride  should  form  a  yellow- 
is'h-red,  strong-smelling  liquid,  of  a  specific  gravity  of 


INORGANIC  CHEMICAL  PREPARATIONS.          8 1 

1.7,  and  should  -have  a  boiling-point  of  138°.  The 
sulphur  clichloride  should  form  a  dark-red  liquid, 
which  evolves  chlorine  even  at  ordinary  temperatures, 
but  more  rapidly  upon  heating. 


BARIUM  DITHIONATE,   BaS2O6  +  2H2O; 
DITHIONIC  ACID,  H2S2O6  +  *H2O. 

Levigate  100  grams  of  finely  pulverized  pyrolusite 
by  stirring  it  in  a  large  mortar  with  water,  decant,  and 
grind  the  residual  coarser  powder  with  more  water. 
Continue  the  grinding  and  levigation  until  all  the 
mineral  remains  suspended  in  water;  let  it  settle  in 
a  tall  cylinder,  siphon  off  the  water,  and  add  only  J 
liter  of  water  to  the  pyrolusite  in  a  liter  flask.*  Pass 
a  current  of  sulphur  dioxide  into  the  flask,  and,  by  cool- 
ing well  on  the  outside  with  ice,  prevent  a  considerable 
rise  in  temperature  of  the  contents  of  the  flask.  When 
the  -principal  portion  of  the  pyrolusite  has  gone  into 
solution,  add  to  the  heated  liquid  concentrated  barium 
hydroxide  in  a  dish,  until  a  filtered  test  no  longer 
gives  a  flesh-colored  precipitate  with  ammonium  sul- 
phide. Filter  the  precipitate,  extract  it  with  hot 
water,  unite  the  filtrates,  and  treat,  while  hot,  with 
carbon  dioxide  until  the  alkaline  reaction  disappears. 

*  Precipitated  manganese  dioxide  may  be  used  immediately  for 
this  experiment  without  any  further  treatment. 


82  INORGANIC  CHEMICAL   PREPARATIONS. 

Barium  dithionate  crystallizes  from  the  filtrate  after 
concentration. 

Dissolve  59  grams  of  the  barium  dithionate  in 
water.  Dilute  20  grams  of  sulphuric  acid  with  water, 
and  add  such  an  amount  of  it  to  the  barium  -salt  that 
a  test,  withdrawn  by  means  of  a  capillary  tube,*  reacts 
neither  with  sulphuric  acid  nor  with  barium  chloride. 
After  filtering  off  the  barium  sulphate,  concentrate 
the  dithionic  acid  in  a  shallow  porcelain  plate  until 
a  specific  .gravity  of  1.347  is  reached,  the  concentra- 
tion being  carried  on  in  vacuo  over  sulphuric  acid. 

REACTION:  The  peroxide  lakes  up  two  atoms  of 
hydrogen  from  two  molecules  of  sulphurous  -acid: 

S03H 
2HSO3H— 2H=  | 

S03H 

The  manganese  salt  of  dithionic  acid  is  decomposed 
by  the  excess  of  barium  hydroxide: 

MnS2O6  +  Bai(OH)2  =  BaS2O6  +  Mn(OH)2. 

TEST:  Barium  dithionate  should  form  beautiful, 
bright,  colorless  crystals,  which,  in  a  powdered  condi- 
tion, lose  all  their  crystal  water  (10.81  %)  at  100°.  De- 
termine the  amount  of  barium  (45.96%  BaO)  by 
igniting  the  dehydrated  salt  and  weighing  the  residual 
barium  sulphate. 

*  See  note,  page  2. 


INORGANIC  CHEMICAL   PREPARATIONS.          83 

THIOPHENE,  C4H4S. 

Literature:    Erdmann,  Praparatenkunde  (Stuttgart  1894),  Bd. 
II,  548. 

Dissolve  572  grams  of  crystallized  sodium  carbon- 
ate in  500  c.c.  of  water  in  a  large  porcelain  dish,  and, 
while  stirring,  gradually  add  236  grams  of  Succinic 
acid  to  the  warm  alkaline  liquid.  After  boiling  off  the 
carbon  dioxide,  evaporate  to  dryness  the  liquid,  which 
now  reacts  neutral,  and  finely  pulverize  the  very  hard 
mass  of  sodium  succinate.  In  order  not  to  be  troubled 
in  this  operation  by  the  dust,  which  strongly  attacks 
the  mucous  membranes,  moisten  the  salt  with  a  few 
drops  of  alcohol.  Dry  the  succinate  very  carefully  at 
140°.  .Intimately  mix  300  grams  of  this  fine  powder, 
which  no  longer  cakes  together,  with  400  grams  of 
phosphorus  trisulphide  (page  65);  place  the  mixture 
in  a  retort,  and  heat  with  a  small  flame  on  a  gas-stove. 
As  soon  as  any  portion  of  the  mass  becomes  dark, 
and  gas  begins  to  be  evolved,  reduce  the  size  of  the 
flame  until  it  is  barely  visible,  in  order  that  the  re- 
action may  not  become  too  violent.  Notwithstanding 
this,  the  reaction,  w'hen  once  started,  continues  vigor- 
ously; and  special  precautions  must  be  taken  to  con- 
dense the  thiophene  vapors,  which  are  mixed  with 
much  gas,  in  order  to  obtain  a  satisfactory  yield 
(40-50%  of  the  theoretical  yield).  For  this  purpose, 
it  is  most  suitable  to  attach  directly  to  the  retort,  a 
glass  tube,  2  cm,  in  diameter  and  1-2  meters  long, 


84          INORGANIC  CHEMICAL   PREPARATIONS. 

Which  acts  as  an  air-condenser.  This  tube  is  joined 
to  a  Liebig  condenser,  which  is  as  long  as  possible 
and  to  which  is  attached  an  air-tight  receiver.  Pass 
the  gases  escaping  from  the  receiver  into  an  absorp- 
tion-flask containing  sodium  hydroxide,  such  as  is  de- 
scribed on  page  124.  Rectify  the  distillate  on  a  water- 
bath,  once  over  powdered  potassium  hydroxide,  and 
again  over  metallic  sodium  whic'h  is  cut  into  fine 
pieces. 

REACTION:  The  sulphide  of  phosphorus  converts 
the  sodium  succinate  into  sulphosuccinyl, 

CH2— COV 

I  \S 

/«3» 

CH2— CCr 
which  rearranges  itself,  forming  dioxythiophene, 

CH=C(OH). 
I  >S. 

CH= C(OH/ 

The  latter  is  reduced  to  thiop'hene  by  the  further  ac- 
tion of  the  sulphide  of  phosphorus. 

TEST:  Thiophene,  C4H4S,  should  form  a  very 
mobile,  limpid  liquid,  boiling  at  83-84°.  The  odor 
should  remind  one  of  benzene,  and,  at  the  same  time, 
of  sulphur  compounds,  but  should  not  be  disagree- 
able. In  a  cooling  mixture  of  solid  carbon  dioxide 
and  ether,  .it  s'hould  solidify  to  a  crystalline  mass. — 
Dissolve  a  small  grain  of  isatin  in  concentrated  sul- 
phuric acid  which  is  not  completely  anhydrous;  add 


INORGANIC  CHEMICAL  PREPARATIONS.          85 

a  drop  of  thiophene  to  10  c.c.  of  pure  benzene  or 
petroleum  ether,  and  shake  i  c.c.  of  each  solution  to- 
gether. The  sulphuric  acid  should  not  become  dark- 
brown  in  color,  but  should  turn  greenish  at  first,  and 
then  should  change  rapidly  into  a  splendid  dark-blue 
color. 


ANHYDROUS   CHROMIC  CHLORIDE,  CrCl3. 

Form  a  paste  by  kneading  together  the  chromic 
oxide  obtained  according  to  the  directions  on  page 


FIGURE  6. — Preparation  of  Anhydrous  Chromic  Chloride. 

87,  while  it  is  still  moist,  with  50  grams  of  powdered 
charcoal  and  thick  starch  paste.  Make  rods  of  it,  cut- 
ting them  in  pieces  about  2-3  cm.  long.  Pack  the 


86          INORGANIC  CHEMICAL   PREPARATIONS. 

pieces,  which  have  been  dried  at  a  gentle  heat  with 
powdered  charcoal,  in  a  Hessian  crucible,  covering 
all  with  a  layer  of  charcoal.  Close  the  crucible  well 
with  an  iron  cover  (see  page  27),  and  ignite  in  a  Ross- 
ler  furnace  (page  117)  for  a  quarter  of  an  hour.  Place 
a  porcelain  tube  upright  in  a  Hessian  crucible,  and  fill 
the  crucible  with  the  pieces  of  chromic  oxide  and 
carbon,  after  they  have  become  cooled  and  have  been 
separated  from  the  charcoal  powder.  Place  in  an 
inverted  position  on  this  crucible  another  one  of  the 
same  size,*  having  an  opening  which  the  porcelain 
tube  fits.  A  short  glass  tube  passes  through  a  second 
opening  at  the  side  of  the  upper  crucible.  Wind 
asbestos  string  about  the  tubes,  thus  rendering  them 
air-tight  at  the  points  where  they  pass  through  the 
openings.  In  order  to  join  both  the  crucib'es  tightly, 
place  a  thin  narrow  strip  of  soft  asbestos  paper  about 
the  place  where  the  edges  meet,  and  carefully  wind 
asbestos  thread  around  it.  Finally,  saturate  the  as- 
bestos thread  with  water-glass,  and  dry  it  at  a  gentle 
heat.  Place  the  crucible  in  a  Rossler  furnace  and 
cover  it  with  two  semicircular  pieces  of  thick  sheet 
iron,  cut  out  in  the  centre,  through  which  the  upper 
crucible  protrudes  from  the  furnace.  Heat  in  a  cur- 
rent of  carbon  dioxide,  until  no  trace  of  moisture  de- 
posits in  the  glass  tube.  Increase  the  temperature 


*  The  fire-clay   crucibles  are   easily   perforated  by  the   metal 
drills  which  are  to  be  found  in  any  mechanic's  workshop. 


INORGANIC  CHEMICAL  PREPARATIONS.          8/ 

to  the  greatest  extent  and  ignite  in  a  current  of  chlo- 
rine, absorbing,  in  an  absorption-bottle  (page  124) 
containing  sodium  hydroxide,  the  unused  chlorine 
which  issues  from  the  glass  tube. 

After  cooling,  the  chromic  chloride  is  found  sub- 
limed in  the  upper  crucible  in  the  form  of  very  bright 
violet-red  plates,  which  are  insoluble  in  water. 

REACTION:   Cr2O3  +  3C  +  6C1  =  2CrQ3  + 


CHROMIC  OXIDE,  Cr2O3. 

Literature:  H.  Schaffer,  Bull,  de  Mulhouse  1893,  97;  P.  Wer- 
ner, ibid,  page  98;  Erdmann,  Lehrbuch  der  anorganischen 
Chemie,  page  641. 

Treat  40  c.c.  of  glycerine,  of  a  specific  gravity  of 
1.23,  at  a  moderate  temperature,  in  a  large  nickel  dish 
or  copper  kettle  of  10  liters  capacity,  with  250  grams 
of  sodium  dichromate  to  which  15  c.c.  of  water  has 
been  added.  Stir  thoroughly,  and  warm  at  the  same 
time  on  a  water-bath.  The  homogeneous  brown  syrup 
which  is  formed  soon  catches  fire  spontaneously, 
upon  stirring  vigorously.  If  this  is  not  the  case, 
ignite  it  with  a  taper  and  cover  the  kettle  immedi- 
ately with  a  suitable  sheet-iron  cover  which  is  ready 
for  that  purpose.  Upon  cooling,  the  kettle  is  found 
loosely  filled  with  green  chromic  oxide.  Wash  it 
with  cold  water,  then  wit'h  warm  water,  filter  on  a 
Bikhner  funnel,  dry  on  the  water-bath;  and  ignite  in 


88  INORGANIC  CHEMICAL  PREPARATIONS. 

a  closed  crucible  the  oxide  thus  purified.  The  yield 
amounts  to  about  100  grams. 

REACTION:  The  reduction  of  the  dichromate  by  the 
glycerine  takes  place  in  such  a  way  that,  besides  the 
chromic  oxide  formed,  sodium  carbonate  is  formed 
also.  This,  together  with  the  small  residue  of  un- 
changed chromate,  is  dissolved  out  with  water.  Any 
remaining  traces  of  organic  matter  are  removed  by 
the  ignition. 

TEST:  Upon  heating  the  beautiful  green  powder 
with  dilute  hydrochloric  acid,  it  should  not  go  into 
solution,  or  only  in  traces. 


VIOLET   CHROMIUM   SULPHATE, 
Cr2(S04)3  +  i8H20. 

Literature:    Etard,  Compt.  rend.  84,  1089. 

Dissolve  100  grams  of  chromic  acid  in  125  c.c.  of 
water,  and  add  to  it  a  cooled  mixture  of  150  grams 
of  concentrated  sulphuric  acid  and  100  c.c.  of  water. 
Place  this  chromic  acid  solution  in  a  porcelain  dish, 
arrange  on  it  a  tripod  carrying  a  porcelain  crucible 
that  contains  50  c.c.  of  ether,  and  cover  the  whole 
with  a  bell  jar.  When  the  ether  has  evaporated 
(and  evaporation  takes  place  pretty  rapidly),  it  must 
be  renewed..  The  chromium  solution  is  completely 
reduced  in  a  few  days  and  converted  into  a  magma  of 
small,  thin,  violet  scales,  to  which  the  thick  green 


INORGANIC  CHEMICAL  PREPARATIONS.          89 

chromium  solution  adheres  and  from  which  it  cannot 
be  freed  by  nitration.  Consequently,  it  is  best  to  dis- 
solve the  whole  mass  in  the  smallest  possible  quan- 
tity of  cold  water  and  precipitate  with  alcohol. 


CHROMYL  CHLORIDE,  CrO2P2. 

Melt,  in  a  Hessian  crucible,  200  grams  of  neutral 
potassium  chromate  with  122  grams  of  salt,  at  not  too 
high  a  temperature,  and  pour  the  molten  mass  upon 
an  iron  plate.  Treat  the  coarsely  powdered  pieces, 
little  by  little,  in  a  large  retort,  'having  a  condenser 
attached,  with  a  mixture  of  66  c.c.  of  fuming  sulphuric 
acid  (specific  gravity  1.906)  and  134  c.c.  of  ordinary 
concentrated  sulphuric  acid.  When  the  reaction, 
which  at  first  is  very  violent,  has  moderated,  heat  until 
no  more  brown  drops  come  over,  and  rectify  the  dis- 
tillate from  a  small  fractioning-flask.  Preserve  the 
chromyl  chloride  in  a  sealed  flask. 

REACTION:   CrO3  +  2HC1-H2O  =  CrO2Cl2. 

TEST:  The  deep  red  oxy  chloride,  which  fumes  in 
the  air,  should  boil  at  116°. 


90  INORGANIC  CHEMICAL  PREPARATIONS. 

CHROMOUS   ACETATE,   (CH3COO)2Cr. 

Literature:  v.  d.  Pfordten,  Annalen  228,  113;  Erdmann, 
Lehrbuch  der  anorganischen  Chemie  (Braunschweig  1898), 
page  645. 

Treat  TOO  grams  of  potassium  dichromate  with 
500  grams  of  fuming  hydrochloric  acid,  in  a  flask; 
and,  after  washing  with  water,  utilize  the  chlorine  that 
is  evolved  in  a  steady  current  upon  heating,  to  prepare 
chlorine  water  or  sodium  hypochlorite.*  Evaporate 
the  rest  of  the  liquid  to  a  very  small  volume  on  the 
gas-stove;  decant  from  the  potassium  chloride  which 
has  separated,  into  a  flask  containing  300  grams  of 
granulated  zinc;  and  afterwards  rinse  the  flask  out, 
with  400  c.c.  of  fuming  hydrochloric  acid.  ;Qose 
the  flask,  in  which  a  very  violent  evolution  of  hydrogen 
takes  place,  with  a  two-hole  rubber  stopper,  provided 
with  glass  tubes  similar  to  the  top  of  a  wash-bottle. 
As  soon  as  the  liquid  becomes  a  clear  bright  blue 
color,  which  reminds  one  of  a  solution  of  copper  sul- 
phate, close  the  glass  tube  that  affords  the  gas  a  free 
exit,  so  that  the  hydrogen,  which  is  still  vigorously 
evolved,  forces  the  liquid  'out  of  the  flask  through  the 
second  tube,  which  reaches  to  the  bottom  of  the 
flask. f  The  liquid  passes,  for  filtration,  to  a  small 

*  It  may  also  be  used  in  the  preparation  of  potassium  chlorate 
(page  13),  silicon  tetrachloride  (page  48),  stannic  chloride  (page 
50),  disulphur  dichloride  (page  80),  chromic  chloride  (page  85), 
or  ferric  chloride  (page  109). 

f  If  the  evolution- of  hydrogen  is  no  longer  sufficiently  strong 


INORGANIC  CHEMICAL  PREPARATIONS.          9 1 

bulb-tube  containing-  asbestos,  and  then  direct,  with- 
out coming  in  contact  with  the  air,  into  a  solution 
of  500  grams  of  crystallized  sodium  acetate  in  2  liters 
of  water.  Wash  the  red  precipitate  a  number  of  times 
by  decantation  with  water  through  which  carbon  di- 
oxide has  been  passed,  and  preserve  as  a  paste. 

REACTION: 

K2Cr207+i4HCl=2KCl+2CrCl3+6Cl+7H2O; 
2CrCl3  +  Zn  =  2CrCl2  +  ZnQ2; 

CHS— COO. 

CrCl2+2CH3.COONa=2NaCl+  >Cr. 

CH3— COOX 

The  reduction  of  the  chromic  chloride  takes  place 
smoothly  and  quickly  only  in  a  concentrated  and  very 
strong  hydrochloric  acid  solution,  with  a  great  excess 
of  zinc.  Chromous  chloride  absorbs  oxygen  from  the 
air  with  great  rapidity,  while  the  insoluble  chromous 
acetate  is  tolerably  stable  in  the  air. 

TEST:  The  red  paste  should  give,  with  dilute  hy- 
drochloric acid,  a  blue  solution,  which  rapidly  turns 
dark-green  with  energetic  absorption  of  oxygen. 

OK 
POTASSIUM   CHLORCHROMATE,  CrO2< 

X  Cl 

Pulverize  100  grams  of  potassium  clichromate,  and 
gently  warm  it  in  a  flask  with  a  mixture  of  100  c.c.  of 

for  this   purpose,   pass   in   carbon   dioxide,   and  by  this  means 

force  the  chromous  chloride  solution  over. 

- 


((  UNIVERSITY   ) 
/ 


92  INORGANIC  CHEMICAL  PREPARATIONS. 

water  and  130  grams  of  pure  fuming  hydrochloric 
acid.  As  soon  as  solution  has  taken  place,  filter,  and 
let  it  stand  quietly.  On  the  following  day,  drain  the 
mother-liquor  from  the  crystals  which  have  separated, 
and  dry  them  on  a  porous  plate.  Yield :  65  grams. 
REACTION: 

KO— CrO2  x  KO— CrO2— Cl 

>O  +  2HC1=-  +H2O. 

KO— CrO/  KO— CrO2— Cl 

TEST:   The  large  red  prisms  or  plates  evolve  chlo- 
rine upon  heating  to  100°. 


SELENIUM,  Se. 

Melt,  in  a  Hessian  crucible,  any  material  or  residues 
containing  selenium,  with  a  mixture  of  equal  parts 
of  sodium  carbonate  and  potassium  nitrate.  Extract 
the  cooled  mass  with  hot  water,  evaporate  the  extract 
to  a  small  volume,  and  by  means  of  a  return  con- 
denser heat  the  liquid,  which  is  made  strongly  acid 
with  concentrated  hydrochloric  acid,  until  no  more 
chlorine  is  evolved.  Dilute  in  a  large  flask  with  a 
large  quantity  of  hot  water,  and  drop  in  sodium  di- 
sulphite,  such  as  is  used  in  the  arts  (40%  solution), 
into  the  boiling  liquid,  just  as  long  as  a  red,  volumi- 
nous precipitate  forms,  which  very  rapidly  mats 
together  into  an  insignificant  black  mass.  After 
settling,  collect  on  a  filter  the  selenium  which  has 
separated  and  dry  it. 


INORGANIC  CHEMICAL  PREPARATIONS.  93 

REACTION:  Upon  melting  with  sodium  carbonate 
and  potassium  nitrate,  material  containing  selenium 
forms  selenates;  but  the  selenic  acid  is  very  rapidly 
reduced  in  a  concentrated  solution  of  hydrochloric 
acid: 

H2SeO4  +  2HC1  =  H2SeO3  +  2C1  +  H2O. 

The  selenious  acid  is  decomposed  by  the  sulphurous 
acid: 

H2SeO3  +  2H2SO3  =  Se  +  2H2SO4  +  H2O. 

TEST:  The  selenium  should  melt  at  217°,  and  solid- 
ify, upon  cooling  slowly,  to  a  dark-gray  crystalline 
mass  of  metallic  lustre.  It  should  dissolve  in  concen- 
trated sulphuric  acid,  with  a  green  color,  and,  upon 
the  addition  of  water,  precipitate  again  from  this  solu- 
tion as  a  voluminous  red  amorphous  precipitate. 
Upon  heating,  it  should  burn  in  the  air,  producing 
a  radish-like  odor,  leaving  no  residue,  and  subliming 
to  selenium  dioxide. 


FLUOSILICIC  ACID,   H2SiF6. 

Mix  100  grams  of  powdered  fluorspar  with  100 
grams  of  dry  quartz  sand  (sea  sand),  and  carefully 
heat  in  a  flask  with  350  c.c.  of  concentrated  sulphuric 
acid.  Conduct  the  gas  evolved  through  an  empty 
bottle  fitted  with  a  safety-tube,  which  is  closed 'by 


94  INORGANIC  CHEMICAL  PREPARATIONS. 

means  of  a  small  amount  of  concentrated  sulphuric 
acid;  and  then  conduct  it  into  a  porcelain  dish,  on  the 
bottom  of  which  is  placed  a  very  small  bottle  con'ain- 
ing  mercury.  Fasten  the  delivery-tube  in  such  a  man- 
ner that  it  dips  under  the  mercury,  and  add  400  c.c. 
of  distilled  water.  After  the  gas  evolution  has  ceased, 
drain  the  silicic  acid  which  has  separated  in  the  water, 
press  it  out,  wash  with  a  little  water  until  the  com- 
bined filtrates  amount  to  400  c.c.,  and  filter  the  still 
somewhat  turbid  acid  through  a  creased  filter. 

REACTION:  Under  the  dehydrating  influence  of  the 
sulphuric  acid,  silicon  tetrafluoride  is  formed: 

SiO2  +  4HF  —  2H2O  =  SiF4; 
but  this  gas  is  decomposed  by  water: 

3SiF4  +  4H20  =  2H2SiF6  +  Si(OH)4. 


TEST:  The  acid  should  give  a  precipitate  with 
barium  chloride,  but  not  with  strontium  chloride  in 
a  hydrochloric  acid  solution  (sulphuric  acid).  To  de- 
termine the  amount  present,  titrate  the  acid  with 
sodium  hydrate  to  an  alkaline  reaction.  The  decom- 
position of  the  acid,  upon  titrating  with  sodium  hy- 
droxide, corresponds  to  the  equation: 

H2SiF6  +  6NaOH  =  6NaF  +  Si(OH)4  +  2H2O. 


INORGANIC  CHEMICAL   PREPARATIONS.  9$ 

PERCHLORIC  ACID,   HC1O4. 

Literature:    Caspari,   Zeitschr.  angew.   Chem.   1893,  68;    Erd- 
mann,  Lehrbuch  der  anorganischen  Chemie,  page  310. 

(1)  Distil,  from  a  retort  not  too  small,  50  grams  of 
potassium  perchlorate  with  a  mixture  of  100  grams  of 
concentrated  sulphuric  acid  and  20  c.c.  of  water.   Free 
the  distillate  from  any  chlorine  dissolved  in  it,  by 
gently  warming,  -treat  with  a  few  centigrams  of  silver 
sulphate  and  barium  carbonate,  filter  the  small  pre- 
cipitates  separately,   wash   with   a   small   amount   of 
water,  and  again  distil  the  filtrate. 

REACTION:  KC1O4  +  H2SO4  =  HC1O4  +  KHSO4. 

The  impure  acid  still  contains  traces  of  hydrochloric 
acid  and  sulphuric  acid,  which  are  removed  by  the 
method  given. 

(2)  Dissolve  56  grams  of  potassium  perchlorate  in 
400  c.c.  of  hot  water  and  add  to  the  hot  solution,  while 
stirring,  70  c.c.  of  fluosilicic  acid  of  a  specific  gravity 
of  1.35  (31%  H2SiF6).     Heat  for  an  hour  with  a  re- 
turn condenser;   cool,  decant,  and  filter  off  the  potas- 
sium fluosilicate  on  a  Biichner  funnel.     On  a  water- 
bath  evaporate  the  clear  solution  of  perchloric  acid, 
as  mudh  as  possible,  and  again  filter,  but  through 
asbestos.    To  obtain  the  filtrate  completely  free  from 
fluosilicic  acid,  treat  the  cold  solution,  after  diluting 
with  an  equal  volume  of  water,  with  a  solution  of 
about  2  grams  of  barium  chloride,  and  evaporate  the 


96  INORGANIC   CHEMICAL  PREPARATIONS. 

liquid,  which  settles  clear  after  a  few  hours,  until  the 
odor  of  hydrochloric  acid  has  disappeared  and  white 
vapors  of  perchloric  acid  begin  to  be  evolved. 

TEST:  A  drop  of  the  acid  should  produce,  in  a  solu- 
tion of  potassium  chloride,  a  thick  crystalline  pre- 
cipitate. 


HYDROBROMIC  ACID,   HBr. 

For  the  preparation  of  hydrobromic  acid  gas,  use 
the  apparatus  illustrated  in  Figure  7.     Place-  in  the 


FIGURE  7. — Preparation  of  Hydrobromic  Acid. 

flask  100  grams  of  dry  benzene  and  a  few  grains  of 
anhydrous  ferrous  bromide  (very  fine  iron  powder  or 
aluminium  powder  may  be  used  in  place  of  ferrous 
bromide).  Gradually  run  in  135  c.c.  of  bromine  from 
a  separating-funnel,  the  end  of  which  is  drawn  out  to 
a  fine  point.  The  mixture  immediately  becomes 


INORGANIC  CHEMICAL  PREPARATIONS.          97 

warm,  and  must  be  placed  in  cold  water  to  prevent 
benzene  or  bromine  from  distilling  over;  but  when 
half  of  the  bromine  has  been  added  (formation  of 
monobrombenzene),  the  reaction  runs  so  quietly  that 
this  precaution  is  no  longer  necessary.  In  order  com- 
pletely to  free  the  gas,  which  is  evolved  in  a  very 
steady  current,  from  the  benzene  and  bromine  vapors 
which  are  carried  over,  use  a  U  tube  attached  to  the 
flask  (Figure  7).  Fill  the  first  half  of  the  tube  with 
ferric  bromide,  FeBr3,*  the  second  half  with  an-' 
thracene,  a  solid  hydrocarbon.  For  the  preparation 
of  a  concentrated  aqueous  hydrobromic  acid,  conduct 
•the  gas  into  a  small  flask,  add  to  it,  little  by  little,  small 
amounts  of  water  from  a  wash  bottle,  and  cool  with 
a  cooling  mixture  of  snow  and  salt.  Preserve  the 
saturated  liquid  in  a  bottle  "having  a  well-ground  stop- 
per and  glass  cap,  or,  wire  the  stopper.  Preserve  in 
a  dark  place. 

REACTION:  C6H6  +  4Br  =  CfiH4Br2  +  2HBr.  The 
small  amount  of  ferrous  bromide  acts  as  a  bromine 
carrier.  The  hydrobromic  acid  w'hich  is  evolved  in  a 
very  steady  current,  carries  benzene  vapors  over;  and 
as  these  vapors  are  brominated  in  the  tube  containing' 
the  ferric  bromide,  they  consequently  are  retained. 
The  gas  is  freed  from  the  smallest  traces  of  free 
bromine  by  means  of  the  anthracene. 


*  Prepared  by  mixing  25  grams  of  ferrous  bromide  and  3  c.c. 
of  bromine,  keeping  cold. 


98  INORGANIC  CHEMICAL  PREPARATIONS. 

TEST:  The  aqueous  solution  should  be  completely 
colorless,  should  fume  strongly  in  the  air,  and  should 
have  a  specific  gravity  of  at  least  1.78  (the  acid  satu- 
rated at  o°). 


AMMONIUM    BROMIDE,   NH4Br; 
POTASSIUM    BROMIDE,    KBr. 

Run  75  c.c.  of  bromine  slowly  from  a  drop-funnel, 
the  stem  of  which  has  been  drawn  out  to  a  fine  point, 
into  220  c.c.  of  concentrated  (30%)  ammonia  placed 
in  a  flask  surrounded  by  ice-water,  with  the  precaution 
that  the  liquid  remains  strongly  ammoniacal  till  the 
end  of  the  reaction,  shaking  continually  during  the 
addition.  Then  heat  until  the  free  ammonia  'has  been 
driven  off,  and  evaporate  to  crystallization.  Dry  the 
ammonium  bromide  by  heating  gently  in  a  porcelain 
dish  over  a  free  flame.  Yield:  220  grams. 

Dissolve  196  grams  of  ammonium  bromide  in  hot 
water  and  add  200  grams  of  potassium  dicarbonate; 
heat  to  boiling,  and,  after  the  odor  of  the  ammonia 
has  disappeared,  set  aside  to  crystallize. 

REACTION:  4NH3  +  3Br  =  3NH4Br  +  N.  If  the 
solution  becomes  acid,  or  the  bromine  runs  in  too 
rapidly,  bromide  of  nitrogen  may  be  formed  and  may 
give  rise  to  an  explosion. 

TEST:  Heat  a  small  sample  of  the  salts  in  a  small 
retort,  with  a  large  excess  of  iron  ammonium  alum 


INORGANIC  CHEMICAL   PREPARATIONS.  99 

(page  in)  in  aqueous  solution,  whereupon  any  iodine, 
present  passes  over  in  a  free  condition.  Drive  out  the 
bromine  in  the  residue,  by  the  addition  of  a  solution  of 
potassium  permanganate,  and,  after  the  removal  of 
the  bromine,  test  for  chlorine  by  heating  with  alcohol 
the  liquid  which  contains  manganese  peroxide  and 
permanganate;  then  add  yellow  fuming  nitric  acid 
until  the  peroxide  dissolves,  and  test  with  a  drop  of 
silver  nitrate  solution. 

This  separation  of  the  halogens  rests  chiefly  upon 
the  fact  that  ferric  salts  set  iodine  free  from  neutral 
solutions  of  iodides, 

Fe2(S04)3  +  2KI  ==  2FeS04  +  K2SO4  +  2!, 

while  the  bromides  remain  completely  unattacked. 
On  the  other  hand,  even  these  are  completely  decom- 
posed by  ferric  salts,  if  a  small  amount  of  a  strong 
oxidizing  agent  (permanganate)  is  present.  The  chlo- 
rides withstand  completely  the  simultaneous  action  of 
both  these  agents. 


DIBROMBENZENE,  C6H4Br2. 

The  residue  from  the  preparation  of  hydrobromic 
acid  (page  96)  solidifies  to  a  crystalline  mass.  Melt 
it  by  placing  the  flask  in  warm  water,  and  gradually 
bring  the  water  to  boiling.  At  the  same  time,  free  the 
substance  as  much  as  possible  from  the  hydrobromic 


IOO         INORGANIC  CHEMICAL  PREPARATIONS. 

acid  present,  pour  into  a  retort,  and  distil.  The  dis- 
tillate solidifies  to  a  crystalline  mass,  which  should  be 
pressed  out  and  again  distilled,  whereupon  the  main 
portion  passes  over  at  215-220°.  Recrystallize  this 
last  distillate  from  the  same  weight  of  hot  alcohol. 
Yield:  about  no  grams  of  pure  dibrombenzene. 

REACTION:  Together  with  the  dibrombenzene, 
there  are  formed  some  liquid  monobrombenzene  and 
0-dibrombenzene,  which  are  removed  by  the  pressing, 
while  the  higher  brominated  products  remain  in  the 
residue  from  the  distillation. 

TEST:  Dibrombenzene  forms  white  monoclinic 
prisms  or  plates.  It  should  melt  at  87-88°  and  boil 
at  219°. 


POTASSIUM  IODIDE,  KL 

Suspend  6  grams  of  pure  iron  powder  in  50  c.c.  of 
water  in  a  small  flask,  and  gradually  add  25  grams  of 
iodine,  keeping  the  liquid  cool.  At  the  end  of  the 
reaction,  there  must  still  be  some  excess  of  iron  pres- 
ent. Filter  it  off,  wash  with  a  little  water,  and  add  5 
grams  of  iodine  to  the  filtrate.  Dissolve  16.5  grams 
of  potassium  carbonate  in  50  grams  of  hot  water  in 
a  porcelain  dish,  and  add  the  iodide  of  iron  to  the  boil- 
ing solution.  Black  ferroferric  oxide  separates  with 
the  vigorous  evolution  of  carbon  dioxide.  Filter,  and 
evaporate  to  crystallization. 


INORGANIC  CHEMICAL  PREPARATIONS.        IOI 

REACTION:  A  mixture  of  ferrous  and  ferric  iodides 
is  formed,  which  by  this  decomposition  with  alkalies 
gives  ferroferric  oxide,  whidi  is  easily  filtered  off. 

TEST:  The  potassium  iodide,  in  sulphuric  acid  solu- 
tion, should  not  turn  starch  paper  blue,  and  must 
show  itself  free  from  bromine  and  chlorine,  according 
to  the  method  of  separating  the  halogens  on  page  98. 


POTASSIUM  IODATE,  K2I2O6. 

Literature:  Groger,  Zeitschr.  angew.  Chem.  1894,  13;  Erd- 
mann,  Lehrbuch  der  anorganischen  Chemie,  page  338. 

Dissolve  40  grams  of  pure  potassium  perman- 
ganate in  i  liter  of  hot  water,  add  20  grams  of  potas- 
sium iodide  dissolved  in  a  small  amount  of  water,  heat 
on  a  water-bath  for  20-30  minutes,  and  drop  in  alcohol 
until  the  liquid,  which  is  reddened  by  the  excess  of 
the  permanganate,  is  decolorized;  then  filter.  Wash 
with  hot  water  the  precipitate  of  potassium  man- 
ganite,  which  remains  on  the  filter.  Then  treat  the 
alkaline  filtrate  with  acetic  acid,  until  it  reacts  dis- 
tinctly acid,  evaporate  to  about  50  c.c.,  cool,  pour  off 
the  mother-liquor  from  the  granular  crystals  of  potas- 
sium ioctate  which  separate,  wash  the  crystals  re- 
peatedly with  strong,  pure  alcohol,  and  dry.  Yield: 
23-25  grams. 

REACTION: 

2KI  +  4KMnO4  =  K2I2O6  +  2K2Mn2O5. 


102         INORGANIC  CHEMICAL  PREPARATIONS. 

Acidifying  with  acetic  acid  is  necessary;  for,  other- 
wise, some  alkali  persistently  adheres  to  the  potassium 
iodate. 

TEST:  The  potassium  iodate  must  react  completely 
neutral,  and  an  aqueous  solution  should  neither  turn 
yellow,  even  upon  standing  for  a  long  time  with  di- 
lute sulphuric  acid,  nor  react  with  starch  paste.  Dis- 
solve in  50  c.c.  of  water  0.3538  gram  of  dry  pulverized 
potassium  iodate,  with  the  addition  of  about  2  grams 
of  potassium  iodide;  add  5  c.c.  of  dilute  hydrochloric 
acid,  and  titrate  with  thiosulphate  solution  until  de- 
colorized. 10.00  c.c.  of  normal  thiosulphate  solution 
are  necessary.  Pure  potassium  iodate  can  also  serve 
as  a  standard  in  alkalimetry.  For  this  purpose,  dis- 
solve in  50  c.c.  of  water  about  0.4  gram  of  potassium 
iodate  with  2.5  grams  of  potassium  iodide;  add  10 
c.c.  of  nearly  normal  acid,  which  is  to  be  standardized; 
and  with  the  normal  thiosulphate,  standardized  in  the 
manner  mentioned  above,  determine  the  iodine  which 
has  separated.  If,  for  example,  in  place  of  10.00  c.c., 
only  9.50  c.c.  of  thiosulphate  are  used,  the  factor  of 
the  acid  solution  to 'be  standardized  is  not  i.oo,  but 
0.950. 


IODINE  TRICHLORIDE,   ICla. 

Heat  20  grams  of  iodine  gently  in  a  small  retort, 
the  neck  of  which  is  connected  with  a  weighed  glass 


INORGANIC  CHEMICAL  PREPARATIONS.         IO3 

balloon,  the  balloon  being  filled  with  chlorine  and 
closed,  but  connected  with  a  Kipp  apparatus  (page 
12 1)  for  generating  chlorine.  As  soon  as  the  iodine 
vapors  enter  the  balloon,  a  rapid  absorption  of  chlo- 
rine takes  place,  and  reddish-yellow  crystals  of  the 
chloride  of  iodine  form  and  attach  themselves  firmly 
to  the  walls.  At  the  end  of  the  operation,  pass  dry 
carbon  dioxide  through  the  balloon,  in  order  to  drive 
out  the  excess  of  chlorine.  Dissolve,  in  ten  times 
their  weight  in  water,  the  crystals  which  cannot  be 
mechanically  removed  from  the  balloon,  and  preserve 
as  a  solution  of  chloride  of  iodine. 

TEST:  Iodine  trichloride  forms  an  orange-colored 
crystalline  powder  of  a  suffocating  odor,  and  easily  dis- 
solves in  water  to  a  clear  yellow  solution.  Ammonia 
should  precipitate  from  a  solution  the  black  and  very 
explosive  iodide  of  nitrogen.  Chloroform  should  ex- 
tract no  iodine  from  an  aqueous  solution,  but  should 
do  so  after  the  addition  of  some  stannous  chloride. 
Upon  heating,  iodine  trichloride  should  be  converted 
into  a  brown  vapor,  leaving  no  residue,  the  vapors  re- 
condensing  to  an  orange-colored  sublimate. 


IODINE   PENTOXIDE,   I2OB. 

Treat  30  grams  of  iodine,  in  a  small  retort,  with  158' 
grams  of  water  mixed  with  nitric  acid  free  from  the 
oxides  of  nitrogen  (page  59).  The  reaction  begins 


104        INORGANIC  CHEMICAL  PREPARATIONS. 

upon  shaking,  and  is  hastened  by  gentle  heating.  The 
red  vapors  that  are  evolved  are  driven  off  by  a  strong 
current  of  air,  which  is  blown  in  through  a  glass  tube, 
the  tube  being  made  tight  in  the  tubulure  by  means 
of  asbestos  string.  In  spite  of  this,  a  portion  of  the 
iodine  is  always  reduced  again  by  the  oxides  of  nitro- 
gen, and,  volatilizing,  is  condensed  in  a  cooled  re- 
ceiver along  with  any  acid  that  distils.  From  time 
to  time,  stop  the  heating  and,  after  air  has  been  blown 
through  the  distillate,  put  it  back  into  the  retort.  Dis- 
solve in  a  small  amount  of  water  the  white  residue 
which  finally  remains,  and  evaporate  to  dryness  in  a 
porcelain  dish  on  the  gas-stove,  the  anhydride  of  iodic 
acid  remaining  in  the  form  of  white  crystals.  36-37 
grams  of  anhydride  are  obtained,  the  calculated  yield 
being  39.5  grams. 


METALLIC   MANGANESE,   Mn. 

Literature:  Goldschmidt,  Annalen  301,  19;  Erdmann,  Lehr- 
buch  der  anorganischen  Chemie,  page  632. 

Gently  ignite  900  grams  of  pure  powdered  pyrolu- 
site  in  a  fire-clay  crucible;  and,  after  cooling,  grind 
UP  75°  grams  of  the  manganic  oxide  thus  formed, 
with  250  grams  of  aluminium  powder.  Place  2 
grams  of  this  mixture  at  the  bottom  of  the  crucible, 
and  cover  it  "with  a  mixture  of  4^  grams  of  barium 
peroxide  and  \  gram  of  aluminium  powder.  Light 


INORGANIC  CHEMICAL  PREPARATIONS.        10$ 

the  mixture  in  the  crucible  by  the  aid  of  magnesium 
ribbon  that  is -wound  up  and  lighted  at  the  end,  or 
better,  by  a  fuse  made  of  a  mixture  of  aluminium  and 
barium  peroxide,  provided  with  magnesium  ribbon; 
and,  as  the  reaction  progresses,  gradually  add  the  pre- 
pared mixture  to  the  mass  by  means  of  an  iron  spoon. 
Too  large  amounts  of  the  mixture  should  not  be 
added  at  a  time,  so  that  the  reaction  does  not  proceed 
too  vigorously;  but  small  amounts  must  be  added  as 
rapidly  as  possible,  in  order  to  attain  the  heat  neces- 
sary to  melt  the  manganese.  In  order  to  retain  the 
heat  better,  the  crucible,  which  soon  becomes  incan- 
descent on  the  outside,  can  be  packed  in  dry  sand, 
or  in  infusorial  earth.  Let  the  covered  crucible 
cool,  break  it  up,  and,  if  the  operation  has  been  suc- 
cessful, a  dense  regulus  of  metallic  manganese  is 
found  under  a  slag  consisting  essentially  of  crystal- 
lized alumina. 

REACTION  :  Mn2O3  +  2A1  =  A12O3  +  2Mn.  To 
start  the  reaction,  a  very  high  temperature  is  neces- 
sary, such  as  can  be  produced  by  burning  magnesium 
or  by  a  mixture  of  aluminium  and  barium  peroxide. 
Once  started,  the  process  continues  spontaneously 
throughout  the  whole  mass,  with  the  production  of 
much  heat.  If  a  crucible  were  completely  filled  with 
the  mixture  of  manganic  oxide  and  aluminium,  and 
heated  in  a  furnace,  the  reaction  would  take  place 
with  explosive  violence.  By  the  gradual  addition  of 


106         INORGANIC  CHEMICAL  PREPARATIONS. 

the  mixture  to  the  crucible,  it  is  wholly  within  one's 
power  to  regulate  the  process. 

TEST:  The  great  instability  that  manganese,  which 
contains  carbon,  shows  in  the  air  when  in  a  finely 
divided  or  moist  condition,  should  not  be  exhibited 
by  the  metal  when  prepared  by  the  preceding 
method.  Pure  manganese  possesses  the  appearance 
of  bright  pig  iron,  having  a  red  shimmer;  it  is  metallic 
in  lustre  and  capable  of  taking  a  high  polish.  It  is  very 
hard, scratching  glass  and  steel;  is  brittle, but  not  mag- 
netic; and,  upon  heating  in  the  air,  it  shows  a  play  of 
color,  as  in  the  case  of  steel.  If  the  heating  is  con- 
tinued, it  is. covered  with  a  brown  pulverulent  oxide. 
Manganese  is  somewhat  more  difficultly  fusible  than 
iron;  but  it  volatilizes  at  a  very  'high  temperature  with 
remarkable  ease.  Treat  a  sample  with  an  excess  of 
dilute  hydrochloric  acid:  the  metal  should  dissolve 
to  a  clear  solution,  with  the  vigorous  evolution  of  hy- 
drogen. A  hot  solution  should  give  no  turbidity,  or, 
at  most,  a  very  slight  turbidity  with  an  excess  of  am- 
monia. By  adding  ammonium  sulphide  to  the  am- 
moniacal  liquid,  flesh-colored  manganese  sulphide 
precipitates,  which,  upon  heating,  gradually  turns 
green. 


INORGANIC  CHEMICAL  PREPARATIONS.        1  07 

MANGANOUS  CHLORIDE,  MnCl2  +  4H2O. 

Evaporate  to  dryness,  in  a  porcelain  dish,  the  resi- 
dues from  the  preparation  of  chlorine  from  pyrolusite 
and  hydrochloric  acid,  and  heat  the  residue,  with  a 
small  flame,  for  some  time  on  the  gas-stove.  Extract 
with  hot  water,  and  precipitate  1/10  of  the  filtrate  with 
an  excess  of  sodium  carbonate  solution.  Wash  the 
precipitate  a  number  of  times  by  decantation  with 
water;  then  add  it  to  the  main  portion  of  the  liquid, 
and  digest  hot,  until  a  filtered  test  gives,  with  am- 
monium sulphide,  a  pure  flesh-colored  precipitate 
which  dissolves  in  acetic  acid  without  leaving  a 
residue.  Then  filter,  and  evaporate  to  crystalliza- 
tion. 

REACTION:  By  'heating  the  dry  chlorides,  and  sub- 
sequently heating  with  water,  compounds  of  the 
trivalent  metals  (iron,  aluminium)  decompose,  form- 
ing insoluble  basic  salts.  Any  remaining  portions  of 
such  compounds  are  precipitated  by  the  manganese 
carbonate  which  is  added: 


3Mn€O3  +  2Fe€l3 

=  3MnCl2  +  2Fe(OH) 

TEST:  The  manganous  chloride  should  be  tested 
particularly  for  the  absence  of  iron,  barium,  calcium, 
and  magnesium  salts. 


108         INORGANIC  CHEMICAL  PREPARATIONS. 


ANHYDROUS   FERROUS   CHLORIDE,   FeQ2. 

Erect  a  retort  exactly  as  in  the  preparation  of  ferric 
chloride  (see  next  preparation),  and,  after  warming  it, 
add  as  rapidly  as  possible  from  a  small  tube,  which 
has  previously  been  warmed  before  opening,  about 
20  grams  of  anhydrous  ferric  chloride.  Conduct  over 
it  a  carefully  dried  current  of  hydrogen  from  a  Kipp 
generator.  The  retort  is  placed  on  a  gas-stove,  but 
the  flame  must  not  be  lighted  until  it  is  certain  that 
the  air  is  completely  driven  from  the  retort.  For  this 
purpose,  the  neck  of  the  retort  is  stoppered  with  a 
cork  carrying  a  tube  w'hich  is  bent  upward;  and  upon 
the  tube  a  test-tube  is  inverted,  which  becomes  filled 
with  the  gases  that  are  evolved.  From  time  to  time, 
close  it  with  the  thumb,  and  test  the  explosiveness 
of  the  gas  by  bringing  the  mouth  of  the  test-tube  into 
contact  with  a  flame.  If  the  gas  burns  quietly,  heat 
the  retort  with  a  moderate-sized  flame,  whereupon 
a  strong  evolution  of  hydrochloric  acid  immediately 
takes  place.  Absorb  the  gas  in  water.  The  operation 
is  finished  when  the  chloride  in  the  retort  has  been 
converted  into  a  white  crystalline  mass,  and  the  evo- 
lution of  hydrochloric  acid  slackens.  Cool  the  con- 
tents of  the  retort  in  a  slow  stream  of  hydrogen,  break 
the  retort  while  it  is  still  warm,  and  preserve  the  fer- 
rous chloride  which  is  collected,  in  the  same  manner 
as  the  anhydrous  ferric  chloride  is  preserved. 


INORGANIC  CHEMICAL  PREPARATIONS.         109 

REACTION:  FeCl3  +  H  =  FeCl2  +  HC1. 

TEST:  Ferrous  chloride  forms  small  white  plates, 
which  are  tolerably  stable  in  the  air,  which  melt  when 
strongly  heated  and,  at  a  very  high  temperature,  sub- 
lime. 


ANHYDROUS  FERRIC  CHLORIDE,  FeQ3. 

To  a  tubulated  glass  retort  of  about  f  liters  capacity, 
add  50  grams  of  polished  iron  wire  of  about  i  mm. 
diameter,  cut  into  pieces  about  6-8  cm.  long.  Heat 
the  retort  strongly  on  the  gas-stove,  and  introduce  a 
rapid  current  of  chlorine  which  has  been  dried  by 
passing  through  two  wash-bottles  containing  sul- 
phuric acid.  Introduce  the  chlorine  through  a  rather 
wide  glass  tube,  which  passes  through  a  cork  stopper 
in  the  tubulure  of  the  retort  and  ends  close  to  the  iron 
wire.  Close  the  neck  of  the  retort  with  a  perforated 
stopper;  conduct  through  a  rubber  tube  the  chlorine 
which  is  evolved,  either  letting  it  escape  out-of-doors, 
or  absorbing  it  in  an  absorption-flask  (page  124)  by 
means  of  caustic  soda  or  alcohol.  After  the  action 
has  continued  for  1-2  hours,  stop  the  gas  current  and 
the  heating,  and  with  dry  carbon  dioxide  drive  out 
the  chlorine  which  fills  the  retort.  Break  the  retort, 
while  it  is  still  hot,  on  a  large  piece  of  smooth  paper, 
and  rapidly  collect  the  ferric  chloride.  The  ferric  chlo- 
ride is  easily  separated  from  the  fragments  of  glass,  as 


HO        INORGANIC  CHEMICAL    PREPARATIONS. 

well  as  from  any  unchanged  iron,  and  is  placed  in  tared 
test-tubes  that  have  suitable  stoppers  and  that  are  dry 
and  warm.  Immediately  seal  the  test-tubes  with  a 
blast-lamp,  taking  care  that  the  gases  from  the  lamp, 
which  carry  aqueous  vapor,  do  not  enter  the  test- 
tubes. 

REACTION:  The  ferric  chloride,  which  is  formed  ac- 
cording to  the  equation  Fe  +  3C1  =  FeCl3,  is  re- 
moved, by  its  volatility,  from  the  reducing  action  of 
the  iron,  and  collects  in  splendid  crystals  in  the  upper 
portions  of  the  retort.*  The  process  is  successful  only 
by  the  complete  exclusion  of  moisture. 

TEST:  Ferric  chloride  forms  a  dark-colored,  com- 
pact mass,  consisting  of  small  plates  that  have  a  green 
iridescence  and  an  extraordinarily  beautiful  metallic 
lustre;  it  deliquesces  rapidly  in  the  air,  forming  brown 
drops.  It  is  easily  soluble  in  water,  evolving  much 
heat;  it  dissolves  also  in  alcoiiol  and  ether,  but  with 
more  difficulty  in  benzene.  These  solutions  are  brown 
in  color  and  react  acid. 


ANHYDROUS   FERROUS   BROMIDE,   FeBr2. 

Strongly  heat  100  grams  of  polished  iron  wire,  in  a 
round-bottomed  flask  on  the  gas-stove,  and  slowly  dis- 

*  Ferrous  chloride  can  form  only  when  the  current  of  chlo- 
rine is  too  slow,  and  it  then  remains  behind  with  the  iron  as  a 
fused  white  mass. 


INORGANIC  CHEMICAL   PREPARATIONS.        Ill 

til  100  c.c.  of  bromine,  by  means  of  a  water-bath,  into 
the  round-bottomed  flask.  The  glass  tube  conduct- 
ing the  bromine  vapors  should  end  close  to  the  bot- 
tom of  the  flask;  but,  in  order  that  no  drop  of  liquid 
bromine  shall  fall  upon  the  hot  glass  and  crack  it, 
it  must  be  protected,  either  by  means  of  a  piece  of  iron 
resting  on  the  bottom  of  the  flask,  or  by  means  of 
asbestos.  When  the  reaction  has  started,  the  tem- 
perature can  be  moderated  somewhat.  At  the  end  of 
the  operation,  pass  dry  air  or  carbon  dioxide  through 
the  apparatus,  and,  after  breaking  the  flask,  collect 
and  preserve  the  preparation  in  the  manner  described 
for  ferric  chloride  (page  109). 


IRON   AMMONIUM   ALUM, 

Fe(NH4)(SO4)2  +  i2H2O. 

Dissolve  400  grams  of  ferrous  sulphate  in  400  c.c. 
of  water,  with  the  addition  of  70  grams  of  concen- 
trated sulphuric  acid.  To  the  boiling-hot  solution 
add  concentrated  nitric  acid  (about  120  grams),  until 
a  diluted  sample  gives  a  pure  rust-colored  precipitate 
with  ammonia.  Evaporate  until  the  solution  thickens 
to  a  resinous  mass,  and  dilute  with  water  to  a  specific 
gravity  of  1.317-1.319.  Treat  300  grams  of  this 
officinal  ferric  sulphate  solution  with  a  solution  of  28 
grams  of  ammonium  sulphate  in  100  grams  of  water, 
and  let  the  mixture  cool  quietly  and  slowly.  Wash 


112        INORGANIC  CHEMICAL   PREPARATIONS. 

the  crystals  with  cold  water,  and  dry  them  without 
heating. 

REACTION:  By  means  of  the  strong  concentration, 
the  last  traces  of  nitric  acid  are  removed  from  the 
ferric  sulphate  solution. 

TEST:  Iron  ammonium  alum  forms  amethyst-col- 
ored octahedra,  the  solution  of  which  should  show 
complete  freedom  from  chlorine  when  treated  with 
silver  nitrate.*  Determine  the  amount  of  iron  pres- 
ent, by  weighing  the  residual  ferric  oxide  obtained  by 
ignition  in  the  presence  of  ammonium  nitrate. 


PRUSSIAN  BLUE. 

Wash  the  residues  from  the  preparation  of  hydro- 
cyanic acid  (page  62),  by  decantation  with  water,  and 
treat  in  a  porcelain  dish  with  commercial  hydrochlo- 
ric acid.  Prepare  a  chloride  of  lime  emulsion  by  sus- 
pending chloride  of  lime  in  water,  and  introduce  it 
through  a  funnel,  the  stem  of  which  extends  to 
the  bottom  of  the  dish,  dipping  beneath  the  hydro- 
chloric acid.  Stir  during  the  addition,  and  continue 
to  add  the  chloride  of  lime  until  the  mass  has  become 
a  beautiful  blue  color  and  the  solution  begins  to  smell 
of  chlorine.  Wash  the  dyestuff  by  decantation  with 

*  This  is  essential  in  the  separation  of  the  halogens,  when 
the  iron  alum  is  used  according  to  the  method  described  on 
page  98. 


INORGANIC  CHEMICAL   PREPARATIONS.        113 

a  dilute  salt  solution,  as  it  does  not  settle  readily  out 
of  water. 

REACTION:  The  residue  from  the  hydrocyanic  acid 
consists  of  the  ferrous  salt  of  hydroferrocyanic  acid, 
which  is  converted  into  the  ferric  salt  by  the  oxidizing 
action  of  the  chloride  of  lime. 


CHLORPLATINIC  ACID,   H2PtQ6 
(from  residues). 

j 

In  case  platinum  residues  contain  filter-paper  and 
other  organic  substances,  first  roast  them  in  a  porce- 
lain dish  on  the  gas-stove,  then  stir  them  with  dilute 
commercial  hydrochloric  acid,  and  completely  reduce 
them  by  the  introduction  of  zinc  bars.  Separate  me- 
chanically the  undissolved  zinc,  decant,  and  extract 
the  impure  platinum  a  number  of  times  with  'hot  water 
and  hydrochloric  acid.  Dissolve  the  residues  in  aqua 
regia,  evaporate  to  a  small  volume,  and  precipitate 
with  a  concentrated  sal  ammoniac  solution.  Filter  off 
the  ammonium  chlorplatinate  and  ignite  in  a  porcelain 
crucible;  extract  the  residual  platinum  sponge  with 
hydrochloric  acid,  dissolve  it  in  aqua  regia,  and  evap- 
orate to  dryness  on  a  water-bath  in  a  weighed  dish, 
adding  a  few  drops  of  'hydrochloric  acid  from  time  to 
time.  Dissolve  the  residue  of  pure  platinic  chloride 
in  10  parts  of  water. 

TEST;    10  drops  of  the  solution  and  one  drop  of 


114        INORGANIC  CHEMICAL   PREPARATIONS. 

sodium  chloride  solution,  evaporated  to  a  very  small 
volume  on  a  watch-glass,  should  give  a  crystalline 
mass  upon  cooling  quietly.  Under  the  microscope, 
only  well-developed  reddish-yellow  prisms  of  sodium 
chlorplatinate  should  be  seen,  and  they  should  not 
be  contaminated  by  amorphous  brown  masses  (iron, 
or  oxide  of  nitrogen  compounds  of  platinic  chloride). 


NATURAL   SYSTEM    OF  THE   CHEMICAL 
ELEMENTS. 


H 

He 

I.O 

4.0 

Li 

Be 

B 

c 

N 

0 

F 

Ne 

7.0 

9.0 

10.9 

11.9 

13.9 

15-9 

18.9 

20.3 

Na 

Mg 

Al 

Si 

F 

s 

Cl 

AT 

22.  Q 

24.2 

26.8 

28.2 

30.8 

31.8 

35-2 

39-7 

K 

Ca 

Sc 

Ti 

Y 

Cr 

Mn 

Fe 

NI 

Co 

38.9 

39-8 

43-7 

47-8 

51.0 

51-7 

54-6 

55-6 

58.4 

59.1 

Cu 

Zn 

Ga 

Ge 

As 

Se 

Br 

63.1 

64  9 

69.0 

71.8 

74-5 

78-4 

79-3 

Rb 

Sr 

Y 

Zr 

Nb 

Mo 

Rn 

in. 

Pd 

84.8 

87.0 

88.3 

90.0 

93-3 

95-3 

100.9 

102.2 

105.6 

Ag 

Cd 

In 

Sn 

Sb 

Te 

I 

107.1 

in.  i 

112.  8 

118.0 

ii9-5 

127.0? 

125.9 

Cs 

Ba 

La 

Ce 

Nd 

Pr 

Sa 

131-9 

136.4 

137.6 

139-1 

139-4? 

142.4? 

148.9 

Gd 

Tb 

Er 

Tu 

154-9 

158.8 

165.0 

169.4 

Yb 

Ta 

W 

Os 

Ir 

Pt 

171.7 

181.2 

182.7 

189.6 

191.7 

193.4 

Au 

Hg 

Tl 

Pb 

Bi 

195.7 

198.8 

202.6 

205.4 

207.0 

Th 

u 

; 

230.9 

237.8 

APPENDIX. 


SOURCES  OF  HEAT. 

Illuminating-gas  is,  in  general,  the  best  heating1 
material  for  the  laboratory.  For  evaporating,  drying, 
or  distilling  at  a  gentle  heat,  the  gas-stove,  shown  in 
the  accompanying  illustration,  is  convenient,  and  is 


FIGURE  8. — Gas-stove  for  Gentle  Heating. 

easily  made  by  any  mechanic.  It  consists  of  a  chim- 
ney, 10-15  cm.  wide,  serrated  at  the  top  and  bottom, 
in  the  middle  of  which  is  a  gas-pipe,  bent  in  the  form 
of  a  circle  of  4-5  cm.  diameter,  through  which  issues 
a  ring  of  flame  through  a  series  of  small  openings. 
The  temperature  is  regulated,  not  only  by  the  supply 
of  gas,  but  is  also  capable  of  such  exact  regulation  by 
the  raising  or  lowering  of  the  circular  flame  that  it 

"5 


Il6  APPENDIX. 

may,  in  many  cases,  advantageously  replace  a  water- 
bath.  Moreover,  operations  which  require  a  higher 
but  exactly  regulated  temperature  (for  example,  the 
preparation  of  the  dry  sulphates  of  the  heavy  metals, 
or  the  separation  of  silver  nitrate  from  an  admixture 
of  cupric  nitrate)  are  extraordinarily  facilitated. 

For  a  higher  temperature  use  the  so-called  Berlin 
burner,  which  differs  essentially  from  the  one  just 
described,  in  that  the  chimney  is  contracted  above  in 
the  s'hape  of  a  cone,  the  top  being  closed  with  wire 
netting  of  very  fine  mesh.  The  gas  and  air  mixture 
burns  above  the  wire  netting  with  only  a  faintly  lumi- 
nous flame.  In -the  simple  Berlin  burners  the  gas  issues 
from  only  one  opening  in  the  middle  of  the  burner, 
6-7  cm.  below  the  wire  netting.  Very  large  heating 
surfaces  may  be  obtained  by  passing  the  gas  through 
a  horizontal  spiral  coil  of  pipe  -that  is  provided  with 
small  holes  and  placed  under  a -wire  netting. 

An  especially  suitable  form  of  Bunsen  burner  is  the 
Dessau  burner,  which,  by  placing  on  a  cap  containing 
wire  netting,  gives  a  very  intimate  mixture  of  the  gas 
with  the  air,  in  consequence  of  which  the  flame  attains 
a  higher  temperature  and  a  much  greater  uniformity. 
Besides  this,  the  wire  netting  keeps  the  flame  from 
striking  back,  according  to  the  principle  of  the  Davy 
safety-lamp. 

With  a  relatively  small  consumption  of  gas,  larger 
crucibles  can  be  brought  to  high  temperatures  by 
means  of  the  Rossler  furnace.  Such  a  furnace,  ade- 


APPENDIX. 


117 


quate  for  pyrochemical  preparations  on  a  small  scale, 
is  shown  in  the  following  cross-section.* 


FIGURE  9. — Cross-section  of  the  Rossler  Gas-furnace. 

The  flame  completely  surrounds  the  crucible;  the 
gases  from  the  combustio-n  pass  out  above  the  crucible 
through  an  opening  in  the  highest  part  of  the  dome, 
then  move  downward,  surrounding  the  whole  of  th'at 
portion-  of  the"  furnace  in  which  the  ignition  takes 
place,  which  is  constructed  of  fire-clay.  The  gases 

*  This  furnace  will  hold  a  crucible  12  cm.  high  and  7  cm.  up- 
per diameter. 


Il8  APPENDIX. 

pass  into  the  chimney  after  they  have  incidentally 
warmed  the  air  that  is  used  in  the  Bunsen  burner 
which  does  the  'heating.  The  chimney  may  be  ex- 
tended to  about  2  meters  in  length ;  and  in  order  that 
the  products  of  combustion  may  be  vigorously  drawn 
up  through  it,  a  flame  is  placed  in  the  chimney.  If 
very  high  temperatures  are  necessary,  use  an  acetylene 
burner  in  this  furnace.  This  is  a  Bunsen  burner  of  a 
somewhat  different  construction,  the  mixture  of  air 
and  acetylene  producing  substantially  higher  tem- 
peratures than  can  be  obtained  with  ordinary  illumi- 
nating gas;  but  it  requires  special  arrangements,  on 
account  of  the  great  rapidity  of  its  explosion-waves, 
so  that  the  burner  will  not  snap  back.  Extreme  tem- 
peratures may  also  be  obtained  by  means  of  alu- 
minium powder  mixed  with  metallic  oxides,  without 
the  use  of  any  furnace  (see  page  104). 


COOLING  MIXTURES. 

A  mixture  of  three  parts  of  ice  and  one  part  of  salt 
serves  for  cooling  between  o°  and — 20°.  Wrap  the  ice 
in  a  cloth  and  pulverize  it  to  a  uniformly  coarse 
powder  by  means  of  a  hammer.  Mix  the  salt  with 
the  powdered  ice,  and  stir  thoroughly  until  the  mix- 
ture is  of  a.  thick  consistency,  in  which  an  inserted 
thermometer  must  show  a  temperature  of  at  least 


APPENDIX.  H9 

For  cooling  to  a  lower  temperature,  down  to 
— 1 00°,  use  a  mixture  of  solid  carbon  dioxide  and 
ether.  The  solid  carbon  dioxide  is  collected  by  letting 
the  liquefied  acid,  such  as  is  found  in  the  market,  es- 
cape into  a  small  bag  made  of  linen  or  flannel.  Place 
the  snow-like  mass  in  a  beaker,  using  a  spoon  made  of 
horn  or  wood,  and  stir  ether  in  with  it,  until  the  mix- 
ture is  of  a  thick  consistency.  To  test  it,  place  a  small 
test-tube  containing  chloroform  in  the  mixture:  it 
should  rapidly  solidify  to  a  crystalline  mass  (melting- 
point  —83°). 


GAS  CURRENTS. 

The  Kipp  apparatus  serves  for  generating  gases 
from  solid  or  liquid  materials;  *  if,  'however,  the  gas 
is  produced  by  the  interaction  of  'two  liquid  sub- 
stances, the  Kipp  apparatus  needs  to  be  supple- 
mented, as  shown  in  Figure  10. 

The  bulb  B  is  filled  with  an  indifferent,  porous 
material,  as  pumice,  upon  which  one  of  the  reagents 
drops  from  T,  passing  through  the  cock  ht  and  the 
mercury  trap  E.  The  other  reagent  is  in  the  bulb  A, 
and  is  forced,  by  the  gas  which  collects,  into  C,  when 
the  cock  h2  leading  to  the  wash-bottle  W  is  closed.  K 
is  a  bulb  apparatus  filled  with  a  proper  liquid  for  ab- 
sorption, so  that  no  gas  can  escape  from  the  upper 
opening  of  the  Kipp.  Figure  n  represents,  on  a 
*  For  the  production  of  hydrobromic  acid,  see  page  96. 


120 


APPENDIX. 


larger  scale,  the  mercury  trap  E,  which  keeps  the  gas 
from  passing  out  through  r  even  when,  by  the  sudden 


FIGURE  10. — Preparation  of  Gases  by  the  Interaction  of  Two 

Liquid  Substances. 


FIGURE  n. 

closing  of  h2,  a  considerable  pressure  arises  in  the 
apparatus.    In  this  case,  the  mercury  rises  high  in  the 


APPENDIX. 


121 


tube  r  and  preserves  the  equilibrium  of  the  pressure 
within  the  apparatus. 

In  the  following  table  the  substances  are  given 
from  which  the  various  gases  are  most  conveniently 
prepared. 

I.    GAS  CURRENTS  FROM  THE  KIPP 
APPARATUS. 


Evolution  of 

Contents  of  bulb  B  : 

Contents  of  bulbs  A  and  C  : 

Chlorine. 

Chloride  of  lime.* 

7  liters  of  commercial 
hydrochloric  acid,  5 
liters  of  water. 

Carbon  dioxide. 

Marble. 

I  liter  of  commercial 
hydrochloric  acid,  I 
liter  of  water. 

Methane. 

Aluminium  carbide. 

Lukewarm  water 

Oxygen. 

Chloride  of  lime.* 

i  liter  of  hydrogen 
peroxide,  50  c.c.  of 
commercial  nitric 
acid. 

Hydrogen  sulphide. 

Sulphide  of  iron. 

I  liter  of  commercial 
hydrochloric  acid,  i 
liter  of  water. 

Nitric  Oxide. 

Copper  turnings. 

Dilute  nitric  acid. 

Hydrogen. 

Zinc. 

i  liter  of  sulphuric 
acid,  4  liters  of  wa- 
ter. 

*  Pressed  into  plates  and  broken  in  pieces. 


122 


APPENDIX. 


II.  GAS  CURRENTS  FROM  THE  APPARATUS, 
FIGURE  10. 


Evolution  of 

Contents  of 
bulb  B\ 

Contents  of  bulb  A  : 

Reagent  flowing  in 
through  T  : 

Acetylene. 

Calcium 
carbide. 

Salt  solution. 

20%  sugar  solution. 

Hydrochloric 
acid. 

Pumice. 

Commercial  hy- 
drochloric acid. 

Concentrated  sul- 
phuric acid. 

Hydrogen 
sulphide. 

Pumice. 

Concentrated  so- 
dium sulphide 
solution. 

i  liter  of  sulphur- 
ic acid,  10  liters 
of  water. 

Sulphur 
dioxide. 

Pumice. 

40$  solution  of 
sodium  disul- 
phite. 

Concentrated  sul- 
phuric acid. 

Nitric 
oxide. 

Pumice. 

Ferrous  chloride 
in  hydrochlo- 
ric acid. 

20$  solution  of  so- 
dium nitrite. 

Nitrous 
anhydride. 

Pumice. 

20%    solution    of 
sodium  nitrite. 

Concentrated  sul- 
phuric acid. 

If  larger  amounts  of  a  gas  are  needed,  the  frequent 
emptying  of  a  Kipp  apparatus,  the  contents  of  which 
are  being  very  rapidly  used  up,  becomes  burdensome; 
especially  in  the  evolution  of  chlorine,  the  pressing 
and  filling  in  of  the  material  also  wastes  much  time. 
Consequently,  in  such  cases,  it  is  better  to  employ  the 
apparatus  shown  in  the  accompanying  illustration 


APPENDIX.  123 

(Figure  12),  which  can  be  filled  with  solid  as  well  as 
with  liquid  substances. 

For  the  evolution  of  chlorine,  place  3.5  kilograms 


FIGURE  12. — Apparatus  for  the  Evolution  of  Chlorine. 

of  chloride  of  lime,  made  up  to  a  paste  with  2  liters 
of  water,  in  a  porcelain  vessel  of  15  liters  content.* 

*  These  vessels  are  serviceable  for  other  purposes  (for  example, 
they  render  excellent  service  in  driving  over  large  amounts  of 
substances  with  steam),  and  may  be  obtained  in  various  sizes. 
The  cover  is  made  tight  by  a  moist  ring  of  pasteboard,  which 
is  clamped  by  means  of  an  iron  ring  provided  with  screws,  which 
surrounds  the  whole  vessel. 


124  APPENDIX. 

It  is  necessary  to  use  about  7  liters  of  commercial  hy- 
drochloric acid.  Regulate  the  introduction  of  the 
acid  by  means  of  a  pinch-cock,  and  control  it  by  the 
air-bubbles  which  rise  through  the  hydrochloric  acid 
in  the  reservoir,  the  reservoir  being  fitted  with  a  cork 
through  which  a  glass  tube  passes,  dipping  into  the 
acid. 

PURIFICATION  OF  GAS  CURRENTS. — A  wash-bottle 
of  the  accompanying  shape  (Figure  13)  is  suitable 


FIGURE  13. — Gas  Washing-bottle. 

for  gas  currents,  and  may  contain  water,  caustic  soda, 
or  concentrated  sulphuric  acid,  as  may  be  desired.  In 
this  bottle,  which  is  constructed  without  stoppers,  the 
gas  passes  through  a  large  number  of  small  openings, 
and  is  well  broken  up  in  the  liquid,  the  latter,  there- 
fore, acting  very  thoroughly.  These  glass  bottles  are 
provided  with  a  wooden  support. 

The  removal  of  arsenuretted  hydrogen  from  hydro- 
gen and  hydrogen  sulphide  is  best  accomplished  by 


APPENDIX.  125 

means  of  iodine.*  Pass  the  gas,  which  has  been  washed 
with  water,  and  consequently  contains  aqueous  vapor, 
through  a  tube  30-40  cm.  in  length,  in  which  4  grams 
of  iodine  are  placed  in  such  a  manner  that  thin  layers 
of  iodine  crystals  are  separated  by  glass  wool.  Wash 
the  gas,  as  it  leaves  the  tube,  with  caustic  soda  and 
water.  Purify  chlorine  gas  from  the  hydrochloric  acid 
gas  which  it  always  contains,  by  washing  it  with  per- 
manganate solution.f 

USE  OF  LIQUEFIED  GASES. — Carbon  dioxide,  sul- 
phur dioxide,  and  ammonia,  which  have  recently  come 
into  the  market  in  a  liquefied  form,  are  specially  suit- 
able for  use,  as  they  need  no  further  purification.  The 
gas  currents  obtained  from  the  cylinders  containing 
the  liquefied  gases,  have  the  great  advantage  over 
those  obtained  from  a  Kipp  apparatus,  in  that  they 
are  almost  completely  free  from  air;  for  example,  the 
carbon  dioxide  obtained  in  this  way  can  be  used  very 
well  for  nitrogen  determinations  by  the  Dumas 
method.  In  order  to  regulate  the  gas  currents  ex- 
actly, notwithstanding  the  very  high  pressure  in  the 
cylinders,  a  reducing-valve  with  a  pressure-gauge  can 
be  used  to  advantage.  It  is  not  advisable  to  use 
liquid  chlorine  and  liquid  acetylene;  for  these  sub- 
stances cannot  be  handled  with  sufficient  safety. 

*  O.  Jakobsen,  Berichte  d.  d.  chem.  Ges.  20,  1998. 
f  Hampe,  Chemiker  Zeitung  14,  1777. 


126 


APPENDIX. 


INTRODUCTION  OF  GASES  INTO  LIQUIDS. 

For  the  absorption  of  gases  by  liquids,  flasks  or 
bottles  closed  air-tight  can  be  conveniently  used,  the 
absorption  being  aided  by  shaking.  This  is  espe- 
cially important  with  poisonous  gases  and  gases 
having  a  bad  odor,  the  escape  of  w'hich  into  the  air 
would  cause  considerable  annoyance.*  If  only  small 
amounts  of  such  gases  are  necessary,  they  are  readily 
used  in  aqueous  solution.  A  solution  of  hydrogen 
sulphide  is  troublesome,  on  account  of  its  instability. 


FIGURE  14. — Tube  for  the  Introduction  of  Gases  into  Liquids. 

Preserve  the  hydrogen  sulphide  solution  in  bottles 
made  of  dark  glass;  by  the  addition  of  glycerine,  the 
stability  of  the  solution  is  increased.!  It  is  of  great 
importance  in  introducing  gases  into  liquids,  as  well 
as  in  washing  them  (see  page  124),  that  the  gas  be 

*  Grabe,  Berichte  d.  d.  chem.  Ges.  31,  2981. 
t  Shilton,  Chem.  News  625  180. 


APPENDIX. 


127 


passed  into  the  liquid  in  the  finest  possible  state  of 
subdivision.  For  this  purpose,  the  bulb  tube,  which 
is  perforated  with  small  holes,  as  represented  in 
Figure  14,  is  very  serviceable. 

ABSORPTION  OF  TROUBLESOME  GASES. — For  the 
absorption  of  troublesome  gases,  use  two  of  the  wash- 
bottles  previously  described,  or,  if  larger  amounts  of 
gases  are  to  be  handled,  two  Woulff  bottles,  con- 
nected in  the  manner  shown  in  Figure  15. 


FIGURE  15. — Absorption  of  Troublesome  Gases. 

This  arrangement  offers  the  advantage  that  it  pre- 
cludes the  sucking  back  of  the  absorbing  medium  by 
the  stoppage  of  the  flow  of  gas. 


128  APPENDIX. 


ATOMIC  WEIGHTS  OF  THE  74  ELEMENTS. 

.Under  H  =  i  are  found  the  values  calculated  with 
reference  to  the  most  recent  determinations,  and 
agreeing  closely  with  the  tables  of  F.  W.  Clarke, 
which  appeared  in  February,  1899.*  Under  O  =  16 
are  the  values  adopted  by  the  committee  of  the  Ger- 
man Chemical  Society  in  1898.!  The  new  elements, 
suc'h  as  coronium,  polonium,  radium,  monium,  ether- 
ion,  krypton,  neon,  xenon,  metargon,  etc.,  are  not  in- 
cluded in  this  table,  as  the  data  concerning  them  are 
not  sufficiently  precise. 


H  =  i. 

O  =  16. 

Aluminium  

Al 

26.8 

27-1* 

Antimony  

Sb 

II9-5 

1  2O 

Argon  

Ar 

39-7 

40  (?) 

Arsenic  

As 

74-5 

75 

Barium  

Ba 

136.4 

137-4 

Beryllium  

Be 

9.0 

9.1 

Bismuth  

Bi 

207.0 

208.5(?) 

Boron  , 

B 

10.9 

II 

Bromine  

Br 

79-3 

79.96 

Cadmium  

Cd 

in.  5 

112 

Caesium  

Cs 

131-9 

133 

Calcium  

Ca 

"39-8 

40 

Carbon  

C 

11.9 

12.  OO 

Cerium  

Ce 

138.3 

140 

Chlorine  

Cl 

35-2 

35.45 

*Jour.  Am.  Chem.  Soc.  21,  213- 
t  Berichte  d.  d.  chem.  Ges.  31,  2761. 

t  According  to  the  recent  researches  of  Thomson,  this  num- 
ber is  too  high. 


APPENDIX.  129 

H   =r    I.  O   =    16. 

Chromium Cr  5i-7               52.1 

Cobalt Co  59.1               59 

Copper Cu  63.1               63.6 

Erbium Er  165.0  166  (?) 

Fluorine F  18.9                19 

Gadolinium Gd  J55-5  

Gallium Ga  69.0               70 

Germanium... Ge  71.8               72 

Gold Au  !95-7  J97-2 

Helium He  4.0                4(?) 

Hydrogen H  i.oo               i.oi* 

Indium In  113-0  114 

Iodine I  125.9  126.85 

Iridium Ir  If)i-7  I93-° 

Iron Fe  55.6               56.0 

Lanthanum La  J37-6  138 

Lead Pb  205.4  206.9 

Lithium Li  7.0                 7-03 

Magnesium Mg  24.1               24.36 

Manganese Mn  54.6               55  .00 

Mercury Hg  198.8  200.3 

Molybdenum Mo  95-3               96.0 

Neodymium Nd  142.5  144  (?) 

Nickel Ni  58.4               58.  7  (?) 

Niobium Nb  93-o               94 

Nitrogen N  13-9               14.04 

Osmium Os  189.6  191 

Oxygen O  15.9               16.00 

Palladium Pd  105.6  106 

Phosphorus P  30.8               31.0 

Platinum Pt  193-4  194.8 

Praseodymium   Pr  r39-4  140  (?) 

Rhodium Rh  102.2  103.0 

Rubidium Rb  84.8               85.4 

Ruthenium Ru  100.9  101.7 

Samarium Sa  149.0  150 (?) 

Scandium Sc  43-8              44. 1 

*  More  exactly,  1.00762. 


130  APPENDIX. 

H  =  i.  O  -  16. 

Selenium Se  78.5  79.1 

Silicon Si  28.2  28.4 

Silver Ag  107.1  107.93 

Sodium Na  22.9  23.05 

Strontium Sr  87.0  87.6 

Sulphur S  31.8  32.06 

Tantalum Ta  181.5  183 

Tellurium Te  127.0  127 

Terbium Tb  158.8  

Thallium Tl  202.6  204.1 

Thorium Th  230.9  232 

Thulium Tu  169.4  

Tin.. Sn  118.0  n8.5(?) 

Titanium Ti  .     47.8  48.1 

Tungsten W  183.0  184 

Uranium U  237.8  239.5 

Vanadium..: V  51.0  51.2 

Ytterbium Yb  171.9  173 

Yttrium Y  88.3  89 

Zinc Zn  64.9  65.4 

Zirconium ...   Zr  90.0  90.6 

NOTE. — The  question-marks  following  the  atomic  weights 
(O  =  16)  of  the  elements  A,  He,  Nd,  Pr,  and  Sa,  indicate  a 
doubt  as  to  the  elementary  nature  of  these  substances.  The 
question-mark  is  introduced  after  the  atomic  weights  of  Ni,  Bi, 
and  Sn,  because  the  Committee  of  the  German  Chemical  Society 
questions  the  accuracy  of  the  decimal  figure. 

In  January,  1900,  this  same  Committee  published  a  revised 
list  of  atomic  weights  (O  =  16),  the.  following  changes  being 
made  :  Cd  =  112.4  ;  Nd  =  143.6  ;  Pr  =  140.5  ;  Th  =  232.5  ; 
Zr  =  90.7.  The  question-marks  have  also  been  removed  from 
A,  He,  Pr,  Sa,  and  Ni. 

F.  W.  Clarke  has  published  his  seventh  annual  report  on 
atomic  weights  (Journal  of  the  American  Chemical  Society, 
February,  1900,  page  70).  This  report  discusses  the  results  pub- 
lished on  atomic-weight  work  during  1899.  The  only  notable 
changes  from  his  previous  table  (Journal  of  the  American 
Chemical  Society,  1899,  page  213)  are  in  the  atomic  weights  of 
cerium,  palladium,  and  tungsten.  ^ 


INDEX  OF  AUTHORS. 


Bunsen,  70 

Caspari,  95 
Clarke,  128,  130 

Erdmann,  5,  10,  39,  45,  47,  50, 
55,  62,  66,  71,  78,  83,  87,  90, 
95,  ioi,  104 

Etard,  88 

Fischer,  77 
Friedheim,  71 

Goldschmidt,  104 
Grabe,  126 
Groger,  ioi 

Hampe,  125 
Jakobsen,  125 
Kassner,  52 


Kriiss,  10 

Lorenz,  50 
L'H6te,  26 

Mellkoff,  41 
Michaelis,  71 
Morse,  34 

v.  d.  Pfordten,  90 
Piloty,  70 
Pissarjewsky,  41 

Schaffer,  87 
Schubert,  8 
Shilton,  126 
Stahl,  74 
Stas,  19 
Stock,  70 

Werner,  87 


INDEX. 


Absorption  of  troublesome  gases,  127 

Aluminium,  action  of  chlorine  on,  43  ;  action  on  manganic  oxide, 
104 

Aluminium  chloride,  anhydrous,  preparation  of,  test,  43 

Aluminium  hydroxide,  preparation  from  cryolite,  42 

Aluminium  oxide,  42 

Ammonium  bromide,  preparation  of  pure,  test,  98 

Ammonium  carbonate,  action  on  calcium  chloride,  25  ;  action  on 
cadmium  nitrate,  29 

Ammonium  chloride,  combination  with  magnesium  chloride,  22  ; 
preparation  of  pure,  60  ;  test,  61 

Ammonium  chlorostannate.     See  pink  salt 

Ammonium  chlorplatinate,  formation  of  and  conversion  into  pla- 
tinum, 113 

Ammonium  dicarbonate,  preparation  of,  test,  61 

Ammonium  iron  alum,  preparation  of,  in  ;  test,  112 

Ammonium  magnesium  arsenate,  69 

Ammonium  magnesium  chloride,  action  on  being  heated,  23 

Ammonium  perborate,  preparation  of,  41  ;  test,  42 

Ammonium    potassium   carbonate.      See    potassium    ammonium 
carbonate 

Antimonious  chloride,  preparation  of,  test,  73 

Antimony,  action  of  sulphuric  acid  on,  75 

Antimony,  basic  chloride  of,  74 

Antimony  oxychloride,  73 

Antimony  sulphate,  preparation  of,  75 

Arsenic,  flowers  of,  71 

133 


1 34  INDEX. 

Arsenic,  white,  71 

Arsenic  acid,  formation  of,  57  ;  preparation  of,  68  ;  tesi,  69  ;  ac- 
tion of  sulphurous  acid  on,  71 

Arsenic  pentasulphide,  70 

Arsenic  silver  nitrate,  27 

Arsenious  acid,  methyl  ester  of,  72.     See  also  arsenious  oxide 

Arsenious  chloride,  27 

Arsenious  oxide,  action  of  nitric  acid  on,  57,  69  ;  preparation  of 
pure,  71  ;  test,  72 

Atomic  weights,  128 

B 

Barium  chloride,  use  of  in  the  purification  of  sodium  chloride,  2  ; 

action  on  sodium  hydroxide,  32 
Barium  dithionate,  preparation  of,  81  ;  test,  82 
Barium  hydroxide,  action  on  potassium  sulphate,  8  ;  preparation 

of,  test,  32  ;  action  on  manganese  dithionate,  82 
Barium  manganate,  31 

Barium  nitrate,  formation  of,  31  ;  decomposition  on  heating,  31 
Barium  nitrite,  31 
Barium  oxide,  preparation  of,  30  ;  test,  31  ;  action  of  oxygen  on, 

33 

Barium  peroxide,  test  for,  31  ;  preparation  of,  33  ;  test,  34 
Barium  peroxide,  hydrated.     See  hydrated  barium  peroxide 
Barium  sulphate.     See  heavy  spar 
Barium  sulphide,  30 

Basic  bismuth  nitrate,  preparation  of,  75 
Benzal  chloride,  action  of  oxalic  acid  on,  45 
Benzaldehyde,  formation  of,  45 
Benzene,  action  of  bromine  on,  96 

Bismuth,  action  of  sodium  nitrate  on,  75  ;  action  of  iodine  on,  76 
Bismuth  hydroxide,  preparation  of,  75 
Bismuth  iodide,  preparation  of,  test,  76 
Bismuth  nitrate,  preparation  of,  75 
Bismuth  nitrate,  basic,  preparation  of,  75 
Bismuth  oxide,  formation  of,  75 
Bismuth  oxyiodide,  preparation  of,  test,  77 
Bleaching  pawder.     See  chloride  of  lime 
Borax,  action  of  magnesium  on,  39  ;  action  of  hydrochloric  acid 

on,  40 


INDEX.  135 


Boric  acid,  preparation  of,  test,  40 

Boron,  preparation  of,  39 

Bulb-tube,  for  the  introduction  of  gases  into  liquids,  126 

Burners,  Berlin,  116  ;  Dessau,  116  ;  Bunsen,  for  acetylene,  118 


Cadmium,  metallic,  action  of  nitric  acid  on,  29 
Cadmium  carbonate,  preparation  of,  29;  test,  30 
Calcium  carbonate,  preparation  of,  25;  test,  26 
Calcium  chloride,  porous,  preparation  of,  24;  test,  25 
Calcium  nitrate,  use  as  a  drying  agent,  57 
Calcium  oxide.     See  lime 

Calcium  phosphide,  preparation  of,  66;  test,  68 
Calcium  plumbate,  formation  of ,  conversion  into  lead  peroxide,  53 
Carbamide.     See  urea 

Celestite,  preparation  of  strontium  hydroxide  from,  27 
Cerium  sulphate,  action  of  sodium  sulphate  on,  55 
Chili  saltpetre.     See  sodium  nitrate 

Chloride  of  lime,  action  on  residues  from  the  preparation  of  hy- 
drocyanic acid,  112;   for  the  preparation  of  chlorine,  123 
Chlorine,  action  on  potassium  carbonate,   13;  on  aluminium,  43; 

on  silicon,  48;  on  sulphur,  So;  on  iodine,  102;  on  iron,  109 
Chlorostannic  acid,  52 

Chlorplatinic  acid,  preparation  of,  test,  113 
Chromic  acid,  action  of  sulphuric  acid  an'd  ether  on,  88 
Chromic  chloride,  anhydrous,  preparation  of,  85  formation  in  the 

preparation  of  chromous  acetate,  90 
Chromic  oxide,  preparation  of,  87;  test,  88 
Chromium  sulphate,  violet,  preparation  of,  88 
Chromous  acetate,  perparation  of,  90;  test,  91 
Chromyl  chloride,  preparation  of,  test,  89 
Citric  acid,  action  on  thorium  hydroxide,  56 
Copper,  action  on   cupric  chloride,  14;  action   of   sulphuric  acid 

on,  16;  preparation  of  pulverulent,  17 
Copper  scale,  see  note,  16;  use  in  the  preparation  of  strontium 

hydroxide,  28 

Cupric  oxide.      See  copper  scale 
Cupric  sulphate,  action  of  potassium  cyanide  on,  15;  preparation 

of,    16;  test,    17;  compounds   with    ammonia    and    potassium 

sulphate,  18* 


136  INDEX. 

Cupric  sulphide,  17 

Cuprous  chloride,  preparation  of,  14;  test,  15 
Cuprous  cyanide,  preparation  of,  15;  test,  16 
Cyanogen,  formation  of,  15,  39 

D 

Diazobenzenesulphonic  acid,  7 

Dibrombenzene,  formation  of,  97  ;  preparation  of,  99  ;  test,  100 

Dioxythiophene,  formation  and  reduction  of,  84 

Disulphur  dichloride,  preparation  of,  test,  80 

Dithionic  acid,  preparation  of,  81 


Elements,  table  of,  with  atomic  weights,  128  ;  natural  system  of, 
114 

Ethyl  bromide,  preparation  of,  45  ;  purification  of,  45,  46  ;  test,  46 

Ethyl  ether,  separation  from  ethyl  bromide,  46  ;  action  on  chro- 
mic acid,  88 

Ethyl  sulphuric  acid,  formation  and  action  on  potassium  bro- 
mide, 46 


Ferric  chloride,  action  of  hydrogen  on  anhydrous,  108  ;  prepara- 
tion of,  109  ;  test,  no 

Ferroferric  oxide,  formation  of,  100 

Ferrous  bromide,  action  on  benzene  and  bromine,  96  ;  prepara- 
tion of,  no 

Ferrous  chloride,  action  on  auric  chloride,  21  ;  preparation  of  an- 
hydrous, 108  ;  test,  109 

Ferrous  sulphate,  action  of  sulphuric  and  nitric  acids  on,  in 

Fluorspar,  action  of  sand  and  sulphuric  acid  on,  93 

Fluosilicic  acid,  preparation  of,  93  ;  test,  94  ;  action  on  potassium 
percolate,  95 

Furnace,  Rossler,  117 

G 

Gas-currents,  119  ;  purification  of,  124 

Gases,  absorption  of  troublesome,  127  ;  liquefied,  use  of,  119,  125 

Gas  furnace,  Rossler,  117 

Gas-stove,  115 


INDEX.  137 

Glycerine,  action  of  sodium  dichromate  on,  87 
Gold,  purification  of,  test,  21 
Grape-sugar  as  a  reducing  agent,  20 

H 

Halogens,  separation  of,  98 

Heat,  sources  of,  115 

Heavy  spar,  preparation  of  barium  oxide  from,  30 

Hydrated  barium  peroxide,  preparation  of,  33  ;  test,  34  ;  action  of 

sulphuric  acid  on,  79 

Hydrobromic  acid,  preparation  of,  96  ;  test,  98 
Hydrocyanic  acid,  action  on  mercuric  oxide,  38  ;  preparation  of 

anhydrous,  62  ;  test,  63 
Hydrogen  peroxide,  action  on  barium  hydroxide,  33  ;  action  on 

boric  acid,  41  ;  preparation  of,  78  ;  test,  79  ;  preservation  of, 

79 

Hydrogen  phosphide.     See  phosphoreted  hydrogen 
Hydrogen  sulphide,  preservation  of,  126 

I 

Iodine,  action  on  bismuth,  76  ;  action  of  nitric  acid  on,  103  ;  ac- 
tion of  chlorine  on,  102 
Iodine  pentoxide,  preparation  of,  103 
Iodine  trichloride,  preparation  of,  102  ;  test,  103 
Iron,  action  of  iodine  on,  101  ;  action  of  chlorine  on,  109 
Iron  ammonium  alum.     See  ammonium  iron  alum 
Iron  filings,  use  for  conducting  heat,  37 

K 
Kipp  apparatus,  120  ;  use  for  various  gases,  121 


Lead,  action  on  sodium  nitrate,  6 

Lead  oxide,  formation  of,  7  ;  action  on  calcium  carbonate,  52 

Lead  peroxide,  preparation  of,  in  a  dry  way,  52  ;  preparation  of, 
in  a  wet  way,  54  ;  test,  54 

Ligroln.     See  petroleum  ether 

Lime,  use  in  purifying  sodium  chloride,  2  ;  use  in  purifying  so- 
dium hydroxide,  4  ;  use  in  purifying  calcium  chloride,  24  ; 
action  on  cryolite,  42  ;  action  on  phosphorus,  66 


138  INDEX. 

M 

Magnesium,  action  on  borax,  39  ;  action  on  sand,  47 

Magnesium  ammonium  arsenate.  See  ammonium  magnesium 
arsenate 

Magnesium  ammonium  chloride.  See  ammonium  magnesium 
chloride 

Magnesium  chloride,  preparation  of  anhydrous,  22  ;  test,  23  ;  ac- 
tion on  commercial  zinc,  26 

Magnesium  silicide,  danger  from  fire,  48 

Manganese,  preparation  of,  104;  test,  106 

Manganese  peroxide.     See  pyrolusite 

Manganic  oxide,  action  of  aluminium  on,  104 

Manganous  chloride,  preparation  of,  test,  107 

Mantles,  55 

Mendeleeff's  system.     See  elements,  natural  system  of 

Mercuric  chloride,  preparation  of,  37;  test,  38 

Mercuric  cyanide,  preparation  of    test,  38 

Mercuric  oxide,  action  in  the  preparation  of  mercuric  chloride,  38; 
action  of  hydrocyanic  acid  on,  38 

Mercuric  oxychloride,  37 

Mercuric  sulphide,  preparation  of,  test,  39 

Mercury,  action  of  sodium  on,  i;  purification  of,  34;  test,  37 

Mercury-trap,  automatic,  36,  120 

Methyl  alcohol,  action  as  a  solvent,  n,  13 

Molecular  silver.     See  silver 

N 
Nitric  acid,  preparation  of,  59;  test,  60;  action  on  phosphorus, 

64;  action  on  iodine,  103 
Nitric  oxide,  formation  of,  30 
Nitrogen  tetroxide,  preparation  of,  test,  57 
Nitrous  anhydride,  7 

O 

Oxalic  acid,  purification  of,  test,  44;  anhydrous,  45 

/* 
P 

Palladium,  2j 

Paracyanogen,  39 

Perchloric  acid,  preparation  of,  95;  test,  96 

Petroleum  ether,  use  for  preserving  sodium,  I 


INDEX.  139 

Phenolphthalem,  use  in  alkalimetry,  5 

Phosphoreted  hydrogen,  spontaneously  inflammable,  68 

Phosphoric  acid,  preparation  of,  64;  test,  65 

Phosphorus,  action  of  nitric  acid  on,  64;  action  on  sulphur,  65; 

action  on  lime,  66 
Phosphorus  trisulphide,   preparation    of,  65;    action    on    sodium 

succinate,  84 
Pink  salt,  52 
Platinum,  occurrence  with  gold,  21;  chloride.       See  chlorplatinic 

acid 

Platinum  sponge,  113 
Potassium  ammonium  carbonate,  formation  from  potassium  cya- 

nate,  12 

Potassium  bromide,  action  of  ethyl  sulphuric  acid  on,  46;  prep- 
aration of,  test,  98 

Potassium  chlorate,  preparation  of,  13;  test,  14 
Potassium  chlorchromate,  preparation  of,  91;  test,  92 
Potassium    chloride,  action  of    sulphuric    acid    on,  10;  formation 

of,  14 

Potassium  chromate,  action  of  sulphuric  acid  on,  89 
Potassium  cobalt  cyanate,  13 
Potassium  cyanate,   preparation  of,  10;  test,   13;  action  towards 

solvents,  13;  action  of  ammonium  sulphate  on,  63,  64 
Potassium  cyanide,  action  on  cupric  sulphate,  15 
Potassium  dichromate,  action  of  hydrochloric  acid  on,  90,  91 
Potassium  disulphate,  preparation  of  pure,  test,  10 
Potassium     ferrocyanide,    action  on  potassium    dichromate,    n; 

action  of  sulphuric  acid  on,  62 

Potassium  hydroxide,  preparation  of  pure,  8;  test,  9 
Potassium  iodate,  preparation  of,  101;  test,  102;  use  in  analysis, 

102 
Potassium  iodide,  action  on  bismuth  nitrate,  77;  preparation  of, 

100;  test,  101 

Potassium  manganite,  101 
Potassium  perchlorate,  formation  of,  14;  action  of  sulphuric  acid 

on,  95 

Potassium  permanganate,  action  on  potassium  iodide,  101 
Potassium  platinic  chloride,  4 
Potassium  sulphate,  action  of  barium  hydroxide  on,  8;  compound 

with  cupric  sulphate,  iS 


I4O  INDEX. 

Powder  of  Algaroth,  74 
Prussian  blue,  preparation  of,  112 
Prussia  acid.     See  hydrocyanic  acid 

Pyrolusite,  action  of  sulphurous  acid  on,  81-  action  of  heat  on, 
104 


Residues,  of  sodium,  preparation  of  sodium  amalgam  from,  i; 
of  silver,  purification  of,  19;  of  mercury,  preparation  of  mer- 
curic chloride,  37;  of  arsenic,  formation  in  the  preparation  of 
nitrogen  tetroxide,  57;  formation  of  crystalline  arsenic  acid 
from,  68;  of  hydrocyanic  acid,  62;  formation  of  prussian  blue 
from,  112;  from  the  preparation  of  chlorine,  preparation  of 
manganous  chloride  from,  107;  of  platinum,  preparation  of 
chlorplatinic  acid,  113 


Sal  ammoniac.    See  ammonium  chloride 

Sand.     See  silica 

Saltpetre,  Chili.     See  sodium  nitrate 

Selenium,  preparation  of,  92;  test,  93 

Silica,  reduction  to  silicon,  47 

Silicide  of  magnesium.     See  magnesium  silicide 

Silicon,  preparation  of  crystallines  47 

Silicon  tetrachloride,  preparation  of,  48 

Silver,  preparation  from  residues  (crystalline  and  molecular),  19; 

test,  20 

Silver  arsenate,  69 

Silver  chloride,  preparation  of  and  action  of  grape-sugar  on,  20 
Sodium,  action  on  mercury,  i;  protection  of,  I 
Sodium  acetate,  use  in  the  preparation  of  bismuth  oxyiodide,  77; 

action  on  chromous  chloride,  91 
Sodium  aluminate,  formation  of,  43 
Sodium  aluminium  fluoride.     See  cryolite 
Sodium  amalgam,  preparation  of,  i;  test,  2 
Sodium  carbonate,  use  in  the  purification  of  sodium  chloride,  2; 

formation  from  cryolite,  42 
Sodium  chloride,  preparation  of,  2;  test,  3 
Sodium  chlorplatinate,  4,  114 


INDEX.  141 

Sodium  dichromate,  action  on  glycerine,  87 

Sodium  disulphite,  solution,  19 

Sodium  hydroxide,  preparation  of,   free  from  carbonate,  4;  test, 

4;  specific  gravity  of  various  strengths,  5;  action  on  barium 

chloride,  32 

Sodium  nitrate,  action  of  lead  on.  6 
Sodium  nitrite,  preparation  of,  6;  test,  7 
Sodium  plumbite,  formation  of,  7;  action  of  chlorine  on,  54 
Sodium  succinate.    See  succinic  acid 

Sodium  sulphite,  use  in  the  purification  of  mercuric  sulphide,  39 
Spiritus  fumans  Labavii.     See  stannic  chloride 
Stannic  chloride,  preparation  of  anhydrous,  50;  test,  52 
Stannous  chloride,  preparation  of  anhydrous,  49;  test,  $0 
Stibnite,  73 

Strontium  hydroxide,  preparation  of,  27;  test,  28 
Strontium  oxide,  29 
Strontium  sulphate.    See  celestite. 
Strontium  sulphide,  28 
Succinic  acid,  action  of  phosphorus  trisulphide  on  the  sodium  salt 

of,  84 

Sulphanilic  acid,  sodium  salt,  action  of  nitrous  acid  on,  7,  8 
Sulphide  of  antimony,  action  of  mercuric  chloride  on,  74 
Sulphide  of  copper,     See  cupric  sulphide. 
Sulphide  of  hydrogen.     See  hydrogen  sulphide. 
Sulphide  of  mercury.      See  mercuric  sulphide. 
Sulphide  of  phosphorus.     See  phosphorus  trisulphide. 
Sulphide  of  strontium.     See  strontium  sulphide. 
Sulphosuccinyl,  conversion  into  dioxythiophene,  84 
Sulphur,  action  on  mercury,  39;  action  on  phosphorus,  65;  action 

of  chlorine  on,  So 

Sulphur  dichloride,  preparation  of,  test,  80 
Sulphur  dioxide.     See  sulphurous  acid 
Sulphurous  acid,  preparation  of,   16;  action  on  arsenic  acid,  71; 

action  on  manganese  peroxide,  81 


Temperature,  high,  115;  low,  118 
Thallium,  occurrence  with  gold,  21 
Thiophene,  preparation  of,  83;  test,  84 


IKDEX. 

Thorium  dioxide,  preparation  of,  55;  test,  56 

Thorium  hydroxide,  56 

Thorium  nitrate,  56 

Thorium  sulphate,  55,  56 

Tin,  action  of  chlorine  on,  50 

Tin  tetrachloride.     See  stannic  chloride 

Turmeric,  test  for  boric  acid,  40 

U 

Urea,  formation  from  potassium  cyanate,  12;  preparation  of,  63; 
test,  64;  nitrate  of,  63 

W 
Wash-bottle,  124,  127] 

Y 

Yellow  prussiate  of  potash.     See  potassium  ferrocyanide 


Zinc,  action  on  cupric  sulphate,  17;  action  on  silver  residues,  19; 
preparation  of,  free  from  arsenic,  26;  use  in  preparing  crys- 
talline silicon,  48 


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Erdmann's  Introduction  to  Chemical  Preparations.     (Dunlap.) 

12m  o,  1  25 

Fresenius's  Quantitative  Chemical  Analysis.    (Allen.) 8vo,  6  00 

Qualitative          "               "            (Johnson.) 8vo,  300 

(Wells.)         Trans. 

16th  German  Edition 8vo,  5  00 

Fuertes's  Water  and  Public  Health 12mo,  1  50 

Gill's  Gas  and  Fuel  Analysis 12mo,  1  25 

Hammarsten's  Physiological  Chemistry.    (Mandel.) 8vo,  4  00 

Helm's  Principles  of  Mathematical  Chemistry.    (Morgan).  12mo,  150 

Hopkins'  Oil-Chemist's  Hand-book 8vo,  3  00 

Ladd's  Quantitative  Chemical  Analysis 12mo,  1  00 

Landauer's  Spectrum  Analysis.     (Tingle.) 8vo,  3  00 

Lob's  Electrolysis  and  Electrosynthesis  of  Organic  Compounds. 

(Lorcuz.) 12mo,  1  00 

Mr  udel's  Bio-chemical  Laboratory 12mo,  1  50 

Mason's  Water-supply 8vo,  5  00 

"      Examination  of  Water 12mo,  1  25 

Meyer's  Radicles  in  Carbon  Compounds.  (Tingle.) 12mo,  1  00 

Mixter's  Elementary  Text-book  of  Chemistry 12mo,  1  50 

Morgan's  The  Theory  of  Solutions  and  its  Results 12rno,  1  00 

Elements  of  Physical  Chemistry 12mo,  200 

Nichols's  Water-supply  (Chemical  and  Sanitary) 8vo,  2  50 

O'Brine's  Laboratory  Guide  to  Chemical  Analysis 8vo,  2  00 

Pinner's  Organic  Chemistry.     (Austen.) 12mo,  1  50 

5 


Poole's  Calorific  Power  of  Fuels 8vo,  $3  00 

Richards's  Cost  of  Living  as  Modified  by  Sanitary  Science. .12mo.  1  00 

"        and  Woodman's  Air,  Water,  and  Food (In  press.} 

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rnetallic) Oblong  8vo,  morocco,  75 

Ruddiman's  Incompatibilities  in  Prescriptions 8vo,  2  00 

Schimpfs  Volumetric  Analysis 12mo,  2  50 

Spencer's  Sugar  Manufacturer's  Handbook 16mo,  morocco,  2  00 

"          Handbook    for    Chemists    of  Beet    Sugar    Houses. 

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Stockbridge's  Rocks  and  Soils 8vo,  2  50 

*  Tollman's  Descriptive  General  Chemistry 8vo,  3  00 

Van  Deventer's  Physical  Chemistry  for  Beginners.    (Boltwood.) 

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Wells's  Inorganic  Qualitative  Analysis 12mo,  1  50 

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Wliipple's  Microscopy  of  Drinking-water 8vo,  3  50 

Wiechmann's  Chemical  Lecture  Notes 12mo,  3  00 

"            Sugar  Analysis ,  Small  8vo,  2  50 

Wulling's  Inorganic  Phar.  and  Med.  Chemistry 12mo,  2  00 


DRAWING. 

ELEMENTARY — GEOMETRICAL — MECHANICAL — TOPOGRAPHICAL. 

Hill's  Shades  and  Shadows  and  Perspective 8vo,  2  00 

MacCord's  Descriptive  Geometry 8vo,  3  00 

"           Kinematics 8vo,  500 

"          Mechanical  Drawing 8vo,  400 

Mahan's  Industrial  Drawing.    (Thompson.) 2  vols.,  8vo,  3  50 

Reed's  Topographical  Drawing.     (H.  A.) 4to,  5  00 

Reid's  A  Course  in  Mechanical  Drawing 8vo.  2  00 

"      Mechanical  Drawing  and  Elementary  Machine   Design. 
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Smith's  Topographical  Drawing.     (Macmillan.) Svo,  2  50 

Warren's  Descriptive  Geometry 2  vols.,  Svo,  3  50 

"        Drafting  Instruments 12mo,  1  25 

Free-hand  Drawing 12mo,  1  00 

"        Linear  Perspective 12mo,  100 

"        Machine  Construction 2  vols.,  Svo,  7  50 

"        Plane  Problems 12mo,  125 

"        Primary  Geometry 12mo,  75 

"        Problems  and  Theorems 8vo,  2  50 

"        Projection  Drawing 12mo,  150 


Warren's  Shades  and  Shadows .8vo,  $3  00 

"        Stereotomy— Stone-cutting 8vo,  250 

Whelpley's  Letter  Engraving 12mo,  2  00 

Wilson's  Free-hand  Perfective (In  press.) 

ELECTRICITY  AND  MAGNETISM. 

ILLUMINATION— BATTERIES— PHYSICS — RAILWAYS. 

Anthony  and  Brackett's  Text-book  of  Physics.     (Magie.)   Small 

8vo,  3  00 

Anthony's  Theory  of  Electrical  Measurements 12mo,  1  00 

Barker's  Deep-sea  Soundings 8vo,  2  00 

Benjamin's  Voltaic  Cell 8vo,  3  00 

History  of  Electricity 8vo,  300 

Classen's  Analysis  by  Electrolysis.    (Henick  and  Boltwood  )  8vo,  3  00 
Crehore  and  Squier's  Experiments  with  a  New  Polarizing  Photo- 
Chronograph 8vo,  3  00 

Dawson's  Electric  Railways  and  Tramways.     Small,  4to,  half 

morocco,  12  50 

*  "Engineering"  and  Electric  Traction  Pocket-book.      16mo, 

morocco,  $5  00 

*  Dredge's  Electric  Illuminations. . .  .2  vols.,  4to,  half  morocco,  25  00 

Vol.  II 4to,  7  50 

Gilbert's  De  magnete.     (Mottelay.) 8vo,  2  50 

Holmau's  Precision  of  Measurements 8vo,  2  00 

"         Telescope-mirror-scale  Method Large  8vo,  75 

Lob's  Electrolysis  and  Electrosynthesis  of  Organic  Compounds. 

(Lorenz.) 12mo,  1  00 

*Michie's  Wave  Motion  Relating  to  Sound  and  Light 8vo,  4  00 

Morgan's  The  Theory  of  Solutions  and  its  Results 12mo,  1  00 

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Thurston's  Stationary  Steam  Engines  for  Electric  Lighting  Pur- 
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*Tillraan's  Heat 8vo,  1  50 

ENGINEERING, 

CIVIL — MECHANICAL— SANITARY,  ETC. 

(See  also  BRIDGES,  p.  4 ;  HYDRAULICS,  p.  9 ;  MATERIALS  OF  EN- 
GINEERING, p.  10 ;  MECHANICS  AND  MACHINERY,  p.  12  ;  STEAM 
ENGINES  AND  BOILERS,  p.  14.) 

Baker's  Masonry  Construction ,.,.,.,...  ,8vo,  $5  00 

"        Surveying  Instruments 12nio,  300 

7 


Black's  U.  S.  Public  Works Oblong  4to,  $  500 

Brooks's  Street-railway  Location 16mo,  morocco,  1  50 

Butts's  Civil  Engineers'  Field  Book 16mo,  morocco,  2  50 

Byrne's  Highway  Construction 8vo,  5  00 

"       Inspection  of  Materials  and  Workmanship 16mo,  3  00 

Carpenter's  Experimental  Engineering 8vo,  6  00 

Church's  Mechanics  of  Engineering — Solids  and  Fluids 8vo,  G  00 

"        Notes  and  Examples  in  Mechanics 8vo,  2  00 

Crandall's  Earthwork  Tables Svo,  1  50 

"         The  Transition  Curve 16mo,  morocco,  1  50 

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*  Drinker's  Tunnelling 4to,  half  morocco,  25  00 

Eissler's  Explosives — Nitroglycerine  and  Dynamite. 8vo,  4  00 

Frizell's  Water  Power (In  press.) 

Folwell's  Sewerage 8vo,  3  00 

"        Water-supply  Engineering 8vo,  4  00 

Fowler's  Coffer-dam  Process  for  Piers .  .8vo.  2  50 

Gerhard's  Sanitary  House  Inspection 1 2mo,  1  00 

Godwin's  Railroad  Engineer's  Field-book 16mo,  morocco,  2  50 

Gore's  Elements  of  Geodesy Svo,  2  50 

Howard's  Transition  Curve  Field-book 16mo,  morocco,  1  50 

Howe's  Retaining  Walls  (New  Edition.) ......  .12mo,  1  25 

Hudson's  Excavation  Tables.     Vol.  II , 8vo,  1  00 

Button's  Mechanical  Engineering  of  Power  Plants Svo,  5  00 

"         Heat  and  Heat  Engines 8vo,  5  00 

Johnson's  Materials  of  Construction Large  Svo,  6  00 

"         Theory  and  Practice  of  Surveying Small  Svo,  4  00 

Kent's  Mechanical  Engineer's  Pocket-book 16mo,  morocco,  5  00 

Kiersted's  Sewage  Disposal 12mo,  1  25 

Mahan's  Civil  Engineering.      (Wood.) 8vo,  500 

Merriman  and  Brook's  Handbook  for  Surveyors. . .  .16mo,  mor.,  2  00 

Merriman's  Precise  Surveying  and  Geodesy 8vo,  2  50 

"          Sanitary  Engineering 8vo,  2  00 

Nagle's  Manual  for  Railroad  Engineers 16mo,  morocco,  3  00 

Ogden's  Sewer  Design 12mo,  2  00 

Patton's  Civil  Engineering 8vo,  half  morocco,  7  50 

Pntton's  Foundations Svo,  5  00 

Philbrick's  Field  Manual  for  Engineers (In  press.) 

Pratt  and  Alden's  Street-railway  Road-beds Svo,  2  00 

Rockwell's  Roads  and  Pavements  in  France 12mo,  1  25 

Searles's  Field  Engineering 16mo,  morocco,  3  00 

"       Railroad  Spiral IGuio,  morocco.  150 

Siebert  and  Biggin's  Modern  Stone  Cutting  and  Masonry. .  ,8vo,  1  50 

Smart's  Engineering  Laboratory  Practice 12mo,  2  50 

Smith's  Wire  Manufacture  and  Uses Small  4to,  3  00 

8 


Spalding's  Roads  and  Pavements l2mo,  $2  00 

Hydraulic  Cement 12mo,  2  00 

Taylor's  Prismoidal  Formulas  aud  Earthwork 8vo.  t  50 

Thurstou's  Materials  of  Construction 8vo,  5  00 

*  Trautwiue's  Civil  Engineer's  Pocket-book 16mo,  morocco,  5  00 

*  "           Cross-section Sheet,  25 

*  *'           Excavations  and  Embankments 8vo,  2  00 

*  "            Laying  Out  Curves 12mo,  morocco,  2  50 

Waddell's  Do  Pontibus  (A  Pocket-book  for  Bridge  Engineers). 

16mo,  morocco,  3  00 

Wait's  Engineering  and  Architectural  Jurisprudence 8vo,  6  00 

Sheep,  6  50 

"      Law  of  Field  Operation  in  Engineering,  etc. .  .(In  press.) 

Warren's  Stereotomy— Stone-cutting 8vo,  2  50 

Webb's  Engineering  Instruments.  New  Edition.  16mo,  morocco,  1  25 

"       Railroad  Construction »8vo,  4  00 

Wegmanu's  Construction  of  Masonry  Dams 4to,  5  00 

Wellington's  Location  of  Railways Small  8vo,  5  00 

Wheeler's  Civil  Engineering 8vo,  4  00 

Wilson's  Topographical  Surveying 8vo,  3  50 

Wolff's  Windmill  as  a  Prime  Mover .8vo,  3  00 

HYDRAULICS. 

WATER-WHEELS — WINDMILLS — SERVICE  PIPE — DRAINAGE,  ETC. 

(See  also  ENGINEERING,  p.  7.) 
Bazin's  Experiments  upon  the  Contraction  of  the  Liquid  Vein. 

(Trautwine.) 8vo,  2  00 

Bovey's  Treatise  on  Hydraulics 8vo,  4  00 

Coffin's  Graphical  Solution  of  Hydraulic  Problems 12mo,  2  50 

Ferrel's  Treatise  on  the  Winds,  Cyclones,  and  Tornadoes. .  .8vo,  4  00 

Folwell's  Water  Supply  Engineering 8vo,  4  00 

Pnertcs's  Water  and  Public  Health 12mo,  1  50 

Ganguillet  &  Kutter's  Flow  of  Water.     (Hering  &  Trautwine.) 

8vo,  4  00 

Hazen's  Filtration  of  Public  Water  Supply 8vo,  3  00 

Herschel's  115  Experiments 8vo,  2  00 

Kiersted's  Sewage  Disposal 12mo,  1  25 

Mason's  Water  Supply 8vo,  5  00 

"     Examination  of  Water .12IT1O,  1  25 

Mcrriman's  Treatise  on  Hydraulics , 8vo,  4  00 

Nichols's  Water  Supply  (Chemical  and  Sanitary) 8vo,  2  50 

Turneaure  and  Russell's  Water-supply (In  press.) 

Wegmann's  Water  Supply  of  the  City  of  New  York 4to,  10  00 

Weisbach's  Hydraulics.     (Du  Bois.) 8vo,  5  00 

Whipple's  Microscopy  of  Drinking  Water 8vo,  3  50 

9 


Wilson 's  Irrigation  Engineering 8vo,  $4  00 

"        Hydraulic  and  Placer  Mining 12mo,  2  00 

Wolff's  Windmill  as  a  Prime  Mover 8vo,  3  00 

Wood's  Theory  of  Turbines 8vo,  2  50 

LAW. 

ARCHITECTURE — ENGINEERING — MILITARY. 

Davis's  Elements  of  Law 8  vo,  2  50 

"      Treatise  on  Military  Law 8vo,  700 

Sheep,  7  50 

Murray's  A  Manual  for  Courts-martial 16mo,  morocco,  1  50 

Wait's  Engineering  and  Architectural  Jurisprudence 8vo,  6  00 

Sheep,  6  50 

"      Laws  of  Field  Operation  in  Engineering (In  press.} 

Winthrop's  Abridgment  of  Military  Law 12mo,  2  50 

MANUFACTURES. 

BOILERS— EXPLOSIVES— IRON — STEEL— SUGAR — WOOLLENS,  ETC. 

Allen's  Tables  for  Iron  Analysis 8vo,  3  00 

Beaumont's  Woollen  and  Worsted  Manufacture 12ino,  1  50 

Bolland's  Encyclopaedia  of  Founding  Terms 12mo,  3  00 

"         The  Iron  Founder 12mo,  250 

"                               "        Supplement 12mo,  250 

Bouvier's  Handbook  on  Oil  Painting 12mo,  2  00 

Eissler's  Explosives,  Nitroglycerine  and  Dynamite 8vo,  4  00 

Ford's  Boiler  Making  for  Boiler  Makers 18mo,  1  00 

Metcalfe's  Cost  of  Manufactures 8vo,  5  00 

Metcalf 's  Steel— A  Manual  for  Steel  Users 12mo,  2  00 

*  Reisig's  Guide  to  Piece  Dyeing 8vo,  25  00 

Spencer's  Sugar  Manufacturer's  Handbook  . .  .  .16mo,  morocco,  2  00 
"         Handbook    for    Chemists    of    Beet    Sugar    Houses. 

16mo,  morocco,  3  00 

Thurston's  Manual  of  Steam  Boilers 8vq,  5  00 

Walke's  Lectures  on  Explosives 8vo,  4  00 

West's  American  Foundry  Practice 12mo,  2  50 

"      Moulder's  Text-book , 12mo,  250 

Wiechniauu's  Sugar  Analysis Small  8vo,  2  50 

Woodbury's  Fire  Protection  of  Mills 8vo,  2  50 

MATERIALS  OF  ENGINEERING 

STRENGTH — ELASTICITY — RESISTANCE,  ETC. 
(See  also  ENGINEERING,  p.  7.) 

Baker's  Masonry  Construction 8vo,  5  00 

Beardslee  and  Kent's  Strength  of  Wrought  Iron  8vo,  1  50 

10 


Bovey's  Strength  of  Materials -8vo,  7  50 

Burr's  Elasticity  and  Resistance  of  Materials Svo,  $5  00 

Byrne's  Highway  Construction Svo,  500 

Church's  Mechanics  of  Engineering — Solids  and  Fluids Svo,  6  00 

Du  Bois's  Stresses  in  Framed  Structures Small  4to,  10  00 

Johnson's  Materials  of  Construction Svo,  6  00 

Lanza's  Applied  Mechanics Svo,  7  50 

Martens's  Testing  Materials.     (Heuning.) 2  vols. ,  Svo,  7  50 

Merrill's  Stones  for  Building  and  Decoration Svo,  5  00 

Merriinan's  Mechanics  of  Materials Svo,  4  00 

"           Strength  of  Materials 12mo,  100 

Patton's  Treatise  on  Foundations ^ Svo,  5  00 

Rockwell's  Roads  and  Pavements  in  France 12mo,  1  25 

Spaldiug's  Roads  and  Pavements 12mo,  2  00 

Thurston's  Materials  of  Construction ....    ,  , Svo,  5  00 

Materials  of  Engineering 3  vols.,  Svo,  8  00 

Vol.  L,  Non-metallic  Svo,  200 

Vol.  II.,  Iron  and  Steel Svo,  3  50 

Vol.  III.,  Alloys,  Brasses,  and  Bronzes Svo,  2  50 

Wood's  Resistance  of  Materials Svo,  2  00 


MATHEMATICS. 

CALCULUS— GEOMETRY — TRIGONOMETRY,  ETC. 

Baker's  Elliptic  Functions Svo,  1  50 

*Bass's  Differential  Calculus .  .12mo,  4  00 

Briggs's  Plane  Analytical  Geometry 12mo,  1  00 

Chapman's  Theory  of  Equations 12mo,  1  50 

Compton's  Logarithmic  Computations 12nio,  1  50 

Davis's  Introduction  to  the  Logic  of  Algebra Svo,  1  50 

Halsted's  Elements  of  Geometry Svo,  1  75 

"        Synthetic  Geometry Svo,  150 

Johnson's  Curve  Tracing 12mo,  1  00 

"         Differential  Equations — Ordinary  and  Partial. 

Small  Svo,  3  50 

"         Integral  Calculus „ 12mo,  1  50 

"  "        Unabridged.     Small  Svo.    (In press.) 

Least  Squares 12mo,  1  50 

*Ludlow's  Logarithmic  and  Other  Tables.     (Bass.) Svo,  2  00 

*       "         Trigonometry  with  Tables.     (Bass.) Svo,  300 

*Mahan's  Descriptive  Geometry  (Stone  Cutting) Svo,  1  50 

Merriman  and  Woodward's  Higher  Mathematics Svo,  5  00 

Merriman's  Method  of  Least  Squares Svo,  2  00 

Rice  and  Johnson's  Differential  and  Integral  Calculus, 

2  vols.  in  1,  small  Svo,  2  50 
11 


Rice  and  Johnson's  Differential  Calculus Small  Svo,  $3  00 

Abridgment  of  Differential  Calculus. 

Small  Svo,  1  50 

Totten's  Metrology Svo,  2  50 

Warren's  Descriptive  Geometry 2  vola.,  Svo,  3  HO 

"        Drafting  Instruments 12mo,  1  25 

"        Free-hand  Drawing 12mo,  100 

"        Linear  Perspective : 12mo,  100 

"        Primary  Geometry 12mo,  75 

Plane  Problems 12ino,  1  25 

"        Problems  and  Theorems Svo,  2  50 

Projection  Drawing 12mo,  150 

Wood's  Co-ordinate  Geometry Svo,  2  00 

"       Trigonometry 12mo,  100 

Woolf's  Descriptive  Geometry Large  Svo,  3  00 

MECHANICS-MACHINERY. 

TEXT-BOOKS  AND  PRACTICAL  WORKS. 
(See  also  ENGINEERING,  p.  7.) 

Baldwin's  Steam  Heating  for  Buildings 12mo,  2  50 

Barr's  Kinematics  of  Machinery Svo,  2  50 

Benjamin's  Wrinkles  and  Recipes 12mo,  2  00 

Chordal's  Letters  to  Mechanics 12mo,  2  00 

Church's  Mechanics  of  Engineering Svo,  6  00 

"        Notes  and  Examples  in  Mechanics Svo,  2  00 

Crehore's  Mechanics  of  the  Girder Svo,  5  00 

Cromwell's  Belts  and  Pulleys 12mo,  1  50 

Toothed  Gearing 12mo,  150 

Compton's  First  Lessons  in  Metal  Working 12mo,  1  50 

Compton  and  De  Groodt's  Speed  Lathe 12mo,  1  50 

Dana's  Elementary  Mechanics 12mo,  1  50 

Dingey's  Machinery  Pattern  Making 12mo,  2  00 

Dredge's     Trans.     Exhibits     Building,      World     Exposition. 

Large  4to,  half  morocco,  10  00 

Du  Bois's  Mechanics.     Vol.  I.,  Kinematics Svo,  3  50 

"               "              Vol.  II.,  Statics Svo,  400 

Vol.  III.,  Kinetics Svo,  350 

Fitzgerald's  Boston  Machinist ISmo,  1  00. 

Flather's  Dynamometers 12mo,  2  00 

Rope  Driving 12mo,  200 

Hall's  Car  Lubrication 12mo,  1  00 

Holly's  Saw  Filing ISmo,  75 

Johnson's  Theoretical   Mechanics.      An   Elementary   Treatise. 
(In  the  press.) 

Jones's  Machine  Design.     Part  I.,  Kinematics Svo,  1  50 

12 


Jones's  Machine  Design.     Part  II.,  Strength  and  Proportion  of 

Machit-.e  Parts 8vo,  $3  00 

Lanza's  Applied  Mechanics 8vo,  7  50 

MacCord's  Kinematics 8vo,  5  00 

Merriman's  Mechanics  of  Materials 8vo,  4  00 

Metcalfe's  Cost  of  Manufactures 8vo,  5  00 

*Michie's  Analytical  Mechanics 8vo,  4  00 

Richards's  Compressed  Air 12mo,  1  50 

Robinson's  Principles  of  Mechanism 8vo,  3  00 

Smith's  Press-working  of  Metals 8vo,  'A  00 

Thurstou's  Friction  and  Lost  Work 8vo,  3  00 

The  Animal  as  a  Machine 12mo,  1  00 

Warren's  Machine  Construction 2  vols.,  8vo,  7  50 

Weisbach's  Hydraulics  and  Hydraulic  Motors.    (Du  Bois.)..8vo,  5  00 
"          Mechanics    of    Engineering.      Vol.    III.,    Part   I., 

Sec.  I.     (Klein.) 8vo,  500 

Weisbach's  Mechanics    of  Engineering.     Vol.   III.,    Part  I., 

Sec.  II.     (Klein.) 8vo,  500 

Weisbach's  Steam  Engines.     (Du  Bois.) 8vo,  5  00 

Wood's  Analytical  Mechanics 8vo,  3  00 

' '      Elementary  Mechanics 12mo,  1  25 

"                 "           Supplement  and  Key 12mo,  125 

METALLURGY. 

IRON— GOLD— SILVER — ALLOYS,  ETC. 

Allen's  Tables  for  Iron  Analysis 8vo,  3  00 

Egleston's  Gold  and  Mercury Large  8vo,  7  50 

Metallurgy  of  Silver Large  8vo,  7  50 

*  Kerl's  Metallurgy — Copper  and  Iron 8vo,  15  00 

Steel,  Fuel,  etc 8vo,  15  00 

Kunhardt's  Ore  Dressing  iu  Europe 8vo,  1  50 

Metcalf's  Steel— A  Manual  for  Steel  Users 12mo,  2  00 

O'Driscoll's  Treatment  of  Gold  Ores 8vo,  2  00 

Thurstou's  Iron  and  Steel 8vo,  3  50 

Alloys 8vo,  250 

Wilson's  Cyanide  Processes 12mo,  1  50 

MINERALOGY   AND  MINING. 

MINE  ACCIDENTS — VENTILATION— ORE  DRESSING,  ETC. 

Barringer's  Minerals  of  Commercial  Value Oblong  morocco,  2  50 

Beard's  Ventilation  of  Mines 12mo,  2  50 

Boyd's  Resources  of  South  Western  Virginia 8vo,  3  00 

"      Map  of  South  Western  Virginia Pocket-book  form,  2  00 

Brush  and  Peufield's  Determinative  Mineralogy.   New  Ed.  8vo,  4  00 


Chester's  Catalogue  of  Minerals 8vo,  $1  25 

Paper,  50 

Dictionary  of  the  Names  of  Minerals 8vo,  3  00 

Dana's  American  Localities  of  Minerals Large  8vo,  1  00 

Descriptive  Mineralogy.  (E  S.)  Large  8vo.  half  morocco,  12  50 

First  Appendix  to  System  of  Mineralogy.   . .  .Large  8vo,  1  00 

"      Mineralogy  and  Petrography.     (J.  D.) 12mo,  2  00 

"      Minerals  and  How  to  Study  Them.     (E.  S.). 12mo,  1  50 

"      Text-book  of  Mineralogy.     (E.  S.)..  .New  Edition.     8vo,  400 

*  Drinker's  Tunnelling,  Explosives,  Compounds,  and  Rock  Drills. 

4to,  half  morocco,  25  00 

Egleston's  Catalogue  of  Minerals  and  Synonyms 8vo,  2  50 

Eisslcr's  Explosives — Nitroglycerine  and  Dynamite 8vo,  4  00 

Hussak's  Rock-forming  Minerals.     (Smith.) Small  8vo,  2  00 

Ihlseng's  Manual  of  Mining 8vo,  4  00 

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